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MELATONIN



Table of Contents
image Melatonin and The Inhibition of Fibroblasts
image Transdermal Delivery of Melatonin
image Melatonin secretion related to side-effects of beta-blockers from the central nervous system
image Oxidative damage caused by free radicals produced during catecholamine autoxidation: Protective effects of O-methylation and melatonin
image Protective effect of melatonin against hippocampal DNA damage induced by intraperitonealadministration of kainate to rats
image Neuroprotection by melatonin from kainate-induced excitotoxicity in rats
image The hypothermic effect of melatonin on core body temperature: Is more better?
image The zinc pool is involved in the immune reconstituting effect of melatonin in pinealectomized mice
image Melatonin and the endocrine role of the pineal organ
image Brief report: Circadian melatonin, thyroid-stimulating hormone, prolactin, and cortisol levels in serum of young adults with autism
image Effects of melatonin and thyroxine replacement on thyrotropin, luteinizing hormone, and prolactin in male hypothyroid hamsters
image Suppression of UV-induced erythema by topical treatment with melatonin (N-acetyl-5-methoxytryptamine). A dose response study
image Melatonin reduces mortality from Aleutian disease in mink (Mustela vison).
image Gastroprotective activity of melatonin and its precursor, L-tryptophan, against stress-induced and ischaemia-induced lesions is mediated by scavenge of oxygen radicals.
image Melatonin: media hype or therapeutic breakthrough?
image Prevention of cytokine-induced hypotension in cancer patients by the pineal hormone melatonin.
image Mechanisms of action of ECT in Parkinson's disease: possible role of pineal melatonin.
image Pineal melatonin functions: possible relevance to Parkinson's disease.
image Locus coeruleus-pineal melatonin interactions and the pathogenesis of the "on-off" phenomenon associated with mood changes and sensory symptoms in Parkinson's disease.
image Pineal melatonin and sensory symptoms in Parkinson disease.
image [Neuroendocrine and psychopharmacologic aspects of the pineal function. Melatonin and psychiatric disorders]
image Studies on the antiinflammatory, immunoregulatory, and analgesic actions of melatonin
image Melatonin effects on behavior: Possible mediation by the central GABAergic system
image Nocturnal plasma melatonin profile and melatonin kinetics during infusion in status migrainosus
image Nocturnal melatonin excretion is decreased in patients with migraine without aura attacks associated with menses
image Urinary melatonin excretion throughout the ovarian cycle in menstrually related migraine
image Nocturnal plasma melatonin levels in migraine: A preliminary report
image The influence of the pineal gland on migraine and cluster headaches and effects of treatment with picoTesla magnetic fields.
image Is migraine due to a deficiency of pineal melatonin?
image Melatonin in humans physiological and clinical studies.
image Treatment of circadian rhythm disorders - Melatonin
image The Mel(1a) melatonin receptor gene is expressed in human suprachiasmatic nuclei
image Circadian sleep-wake disorders
image Melatonin and jet lag
image Melatonin efficacy in aviation missions requiring rapid deployment and night operations
image Melatonin: Between facts and fantasy
image Melatonin: A master hormone and a candidate for universal panacea
image Use of melatonin in circadian rhythm disorders and following phase shifts
image Adapting to phase shifts, II. Effects of melatonin and conflicting light treatment
image Chronobiotics - Drugs that shift rhythms
image Phase shifting the human circadian clock using melatonin
image A double-blind trial of MELATONIN as a treatment for jet lag in international cabin crew.
image MELATONIN and jet lag: confirmatory result using a simplified protocol
image Role of biological clock in human pathology
image Melatonin marks circadian phase position and resets the endogenous circadian pacemaker in humans.
image The role of pineal gland in circadian rhythms regulation.
image Light, melatonin and the sleep-wake cycle.
image Circadian rhythms, jet lag, and chronobiotics: an overview.
image [Chronobiological sleep disorders and their treatment possibilities]
image Chronopharmacological actions of the pineal gland.
image Some effects of MELATONIN and the control of its secretion in humans.
image Daily melatonin intake resets circadian rhythms of a sighted man with non-24-hour sleep-wake syndrome who lacks the nocturnal melatonin rise
image A sighted man with non-24-hour sleep-wake syndrome shows damped plasma melatonin rhythm
image Case study: The use of melatonin in a boy with refractory bipolar disorder
image Rapid reversal of tolerance to benzodiazepine hypnotics by treatment with oral melatonin: A case report
image Improvement of sleep quality by controlled-release melatonin in benzodiazepine-treated elderly insomniacs
image Melatonin - a chronobiotic and soporific hormone
image Evaluation of the antioxidant activity of melatonin in vitro
image Nocturnal melatonin secretion and sleep after doxepin administration in chronic primary insomnia
image Melatonin: From the hormone to the drug?
image Inhibition of melatonin secretion onset by low levels of illumination
image Melatonin replacement corrects sleep disturbances in a child with pineal tumor
image Melatonin replacement therapy of elderly insomniacs
image Improvement of sleep equality in elderly people by controlled-release melatonin
image Sleep-inducing effects of low doses of melatonin ingested in the evening
image Melatonin rhythms in night shift workers
image Effect of melatonin replacement on serum hormone rhythms in a patient lacking endogenous melatonin
image Melatonin administration in insomnia
image Immune effects of preoperative immunotherapy with high-dose subcutaneous interleukin-2 versus neuroimmunotherapy with low-dose interleukin-2 plus the neurohormone melatonin in gastrointestinal tract tumor patients.
image The immunoneuroendocrine role of melatonin.
image Melatonin reduces the severity of dextran-induced colitis in mice.
image Melatonin affects proopiomelanocortin gene expression in the immune organs of the rat.
image Serial transplants of DMBA-induced mammary tumors in Fischer rats as model system for human breast cancer. IV. Parallel changes of biopterin and melatonin indicate interactions between the pineal gland and cellular immunity in malignancy.
image Inhibitory effect of melatonin on production of IFN gamma or TNF alpha in peripheral blood mononuclear cells of some blood donors.
image Specific binding of 2-[125I]iodomelatonin by rat splenocytes: characterization and its role on regulation of cyclic AMP production.
image Pineal-opioid system interactions in the control of immunoinflammatory responses.
image Evidence for a direct action of melatonin on the immune system.
image The immuno-reconstituting effect of melatonin or pineal grafting and its relation to zinc pool in aging mice.
image Multiple sclerosis: the role of puberty and the pineal gland in its pathogenesis.
image Modulation of human lymphoblastoid interferon activity by melatonin in metastatic renal cell carcinoma. A phase II study.
image Modulation of 2[125I]iodomelatonin binding sites in the guinea pig spleen by melatonin injection is dependent on the dose and period but not the time.
image Binding of [125I]-labelled iodomelatonin in the duck thymus.
image Characteristics of 2-[125I]iodomelatonin binding sites in the pigeon spleen and modulation of binding by guanine nucleotides.
image Pinealectomy ameliorates collagen II-induced arthritis in mice.
image 2[125I]iodomelatonin binding sites in spleens of guinea pigs.
image Melatonin: a chronobiotic with anti-aging properties?
image Effect of dose and time of melatonin injections on the diurnal rhythm of immunity in chicken.
image The pineal neurohormone melatonin stimulates activated CD4+, Thy-1+ cells to release opioid agonist(s) with immunoenhancing and anti-stress properties.
image Alterations of pineal gland and of T lymphocyte subsets in metastatic cancer patients: preliminary results.
image Endocrine and immune effects of melatonin therapy in metastatic cancer patients.
image Melatonin modulation of estrogen-regulated proteins, growth factors, and proto-oncogenes in human breast cancer.
image Melatonin inhibition of MCF-7 human breast-cancer cells growth: influence of cell proliferation rate.
image Modulation of cancer endocrine therapy by melatonin: a phase II study of tamoxifen plus melatonin in metastatic breast cancer patients progressing under tamoxifen alone.
image Modulation of estrogen receptor mRNA expression by melatonin in MCF-7 human breast cancer cells.
image Melatonin modulates growth factor activity in MCF-7 human breast cancer cells.
image Role of pineal gland in aetiology and treatment of breast cancer.
image A review of the evidence supporting melatonin's role as an antioxidant.
image Treatment of cancer chemotherapy-induced toxicity with the pineal hormone melatonin.
image Treatment of cancer-related thrombocytopenia by low-dose subcutaneous Interleukin-2 plus the pineal hormone melatonin: A biological phase II study
image Type 2 Th cells as target of the circadian melatonin signal: Relevance in local immunity
image Hematopoietic rescue via T-cell-dependent, endogenous granulocyte- macrophage colony-stimulating factor induced by the pineal neurohormone melatonin in tumor-bearing mice
image Randomized study with the pineal hormone melatonin versus supportive care alone in advanced nonsmall cell lung cancer resistant to a first-line chemotherapy containing cisplatin
image Melatonin increase as predictor for tumor objective response to chemotherapy in advanced cancer patients
image Modulation of the length of the cell cycle of the MCF-7 human breast cancer cells by melatonin
image Melatonin blocks the stimulatory effects of prolactin on human breast cancer cell growth in culture.
image Differences between pulsatile or continuous exposure to melatonin on MCF-7 human breast cancer cell proliferation.
image Effects of melatonin on cancer: studies on MCF-7 human breast cancer cells in culture.
image Neuroimmunotherapy of advanced solid neoplasms with single evening subcutaneous injection of low-dose interleukin-2 and melatonin: preliminary results.
image Tissue changes in glutathione metabolism and lipid peroxidation induced by swimming are partially prevented by melatonin
image Modulation of tumor necrosis factor-alpha (TNF-alpha) toxicity by the pineal hormone melatonin (MLT) in metastatic solid tumor patients
image A biological study on the efficacy of low-dose subcutaneous interleukin-2 plus melatonin in the treatment of cancer-related thrombocytopenia.
image Melatonin prevents death of neuroblastoma cells exposed to the Alzheimer amyloid peptide.
image Daily rhythm of serum melatonin in patients with dementia of the degenerate type.
image The mystery of Alzheimer's disease and its prevention by melatonin.
image Chrono-neuroendocrinological aspects of physiological aging and senile dementia.
image A phase II study of tamoxifen plus melatonin in metastatic solid tumour patients

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Immune effects of preoperative immunotherapy with high-dose subcutaneous interleukin-2 versus neuroimmunotherapy with low-dose interleukin-2 plus the neurohormone melatonin in gastrointestinal tract tumor patients.

J Biol Regul Homeost Agents (ITALY) Jan-Mar 1995, 9 (1) p31-3

Surgery-induced immunosuppression could influence tumor/host interactions in surgically treated cancer patients. Previous studies have shown that high-dose IL-2 preoperative therapy may neutralize surgery-induced lymphocytopenia. Moreover, experimental studies have demonstrated that the immunomodulating neurohormone melatonin (MLT) may amplify IL-2 activity and reduce its dose required to activate the immune system. On this basis, we have compared the immune effects of presurgical therapy with high-dose IL-2 with respect to those obtained with preoperative neuroimmunotherapy consisting of low-dose IL-2 plus MLT. The study included 30 patients with gastrointestinal tract tumors, who were randomized to undergo surgery alone, or surgery plus a preoperative biotherapy with high-dose IL-2 (18 million IU/day subcutaneously for 3 days) or low-dose IL-2 (6 million IU/day subcutaneously for 5 days) plus MLT (40 mg/day orally). Patients underwent surgery within 36 hours from IL-2 interruption. Both IL-2 plus MLT were able to prevent surgery-induced lymphocytopenia. However, mean number of lymphocytes, T lymphocytes and T helper lymphocytes observed on day 1 of postoperative period was significantly higher in patients treated with IL-2 plus MLT than in those receiving IL-2 alone. Moreover, toxicity was less in patients treated with IL-2 and MLT. This biological study shows that both immunotherapy with high-dose IL-2 or neuroimmunotherapy with low-dose IL-2 plus MLT preoperatively are tolerated biotherapies, capable of neutralizing surgery-induced lymphocytopenia in cancer patients. Moreover, the study would suggest that the neuroimmunotherapy may induce a more rapid effect on postoperative immune changes with respect to IL-2 alone.



The immunoneuroendocrine role of melatonin.

J Pineal Res (DENMARK) Jan 1993, 14 (1) p1-10

A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MIIO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as gamma-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.



Melatonin reduces the severity of dextran-induced colitis in mice.

J Pineal Res (DENMARK) Aug 1995, 19 (1) p31-9

Melatonin administration reduces the severity of dextran sodium sulphate (DSS)-induced colitis in mice. After 7 weeks of daily intraperitoneal melatonin administration (150 micrograms/kg), rectal bleeding and occult blood was eliminated in all mice in which colitis was induced by DSS. In addition the frequency and severity of focal lesions in the mucosa was dramatically reduced. Furthermore, weight loss and higher food consumption observed in DSS-treated mice was reversed in DSS-treated mice injected with melatonin. All treated groups exhibited significant alterations in goblet cell distribution as a result of DSS or melatonin administration. Surprisingly, serum melatonin levels were more than 10 times higher in mice that received DSS as compared to controls. The significant improvement in the conditions of melatonin-treated mice might be due to its effect on the smooth muscles of the colon, the blood supply in the mucosa, its capability as an antioxidant and scavenger of free radicals, or its effect on the immune system of the gut. The higher plasma levels of melatonin in DSS-treated mice might be due to a stress-induced increase in the production of gastrointestinal (GIT) melatonin.



Melatonin affects proopiomelanocortin gene expression in the immune organs of the rat.

Eur J Endocrinol (NORWAY) Dec 1995, 133 (6) p754-60

The induction of opioid peptides derived from cells of the immune system is postulated to be the main mechanism involved in the immunomodulatory role of melatonin. In this study, it has been demonstrated for the first time that melatonin can act on the level of proopiomelanocortin (POMC) gene expression. The effect of the pineal hormone, administered in late-afternoon subcutaneous injections, was studied in the immune organs of adult male Wistar rats by means of a highly sensitive reverse transcription polymerase chain reaction method (RT-PCR), followed by polyacrylamide gel electrophoresis and densitometric analysis of the bands. It was demonstrated that melatonin stimulates the expression of the 3rd exon of the POMC gene in the lymph nodes and in bone marrow. No significant effects of the pineal hormone were observed in the spleen and thymus. The study establishes that the formation of short POMC transcripts in the bone marrow and lymph nodes may be upregulated by melatonin. Moreover, the pineal hormone exerts its effect without antigenic stimulation.



Serial transplants of DMBA-induced mammary tumors in Fischer rats as model system for human breast cancer. IV. Parallel changes of biopterin and melatonin indicate interactions between the pineal gland and cellular immunity in malignancy.

Oncology (SWITZERLAND) Jul-Aug 1995, 52 (4) p278-83

Nocturnal (23.00-07.00 h) urinary melatonin and total biopterin (tBI; after acidic oxidation of reduced biopterins) were analyzed during the growth of two passages of a mammary tumor line in female F344 Fischer rats. In addition, nocturnal (02.00-03.00 h) peak concentrations of pineal melatonin in plasma were analyzed when tumors had reached comparable average tumor volumes of 25-30 cm3. Since tetrahydrobiopterin (BH4) is produced by murine macrophages in response to interferon-gamma released by activated T lymphocytes, measurements of tBI can serve to estimate the state of cellular immunity. At passage 2, a slow-growing localized carcinosarcoma, tBI showed a progressing increase during tumor growth reaching more than 200% (p < 0.05-0.005) of controls by the end of the experiment. Urinary and plasma melatonin were elevated by 30-50% (p < 0.05) and 42% respectively. At passage 12, a fast-growing metastasizing sarcoma, a depression of about 20-30% was found for tBI (p < 0.05) and urinary melatonin (p < 0.025); plasma melatonin was depleted by 70% (p < 0.005). Parallel changes of both parameters at each tumor passage indicate a close link between the pineal hormone melatonin and cellular immunity. The opposite trends observed at the two passages indicate a clear stimulation of the immune system and the pineal gland at early but inhibition at advanced stages of cancer.



Inhibitory effect of melatonin on production of IFN gamma or TNF alpha in peripheral blood mononuclear cells of some blood donors.

J Pineal Res (DENMARK) Nov 1994, 17 (4) p164-9

Melatonin, the main pineal hormone, has been shown to influence many biological functions, including the immune response and cancer growth. The purpose of this study was to examine the effect of melatonin on the production of interferon gamma (IFN gamma) and tumor necrosis factor alpha (TNF alpha) by peripheral blood mononuclear cells (PBMC) in culture. Melatonin at physiological concentrations fails to induce production of IFN or TNF by PBMC in culture but causes a dose-related inhibition of production of both cytokines if the PBMC are stimulated with phytohaemagglutinin. This inhibitory effect occurs in only 22% of cases (melatonin-sensitive) but disappears when the cells are stored at 4 degrees C for 4 days. The effect of melatonin appears not to be mediated by opiates nor to be correlated with the age, sex, or blood group of donors, but seems to be influenced by the seasonal time of blood collection. These results provide further evidence for an interaction between melatonin and the immune system and suggest that the effect of melatonin on production of IFN and TNF may be mediated by various factors not yet fully understood.



Specific binding of 2-[125I]iodomelatonin by rat splenocytes: characterization and its role on regulation of cyclic AMP production.

J Neuroimmunol (NETHERLANDS) Mar 1995, 57 (1-2) p171-8

In the present paper we show that pineal hormone melatonin interacts with rat splenocytes through high-affinity binding sites. Binding of 2-[125I]iodomelatonin ([125I]MEL) by splenocytes fulfills all criteria for binding to a receptor site. Binding exhibited properties such as dependence on time and temperature as well as reversibility, saturability, high affinity, specificity, and increased under constant light exposure. Results suggest binding to a single class of binding sites without cooperative interactions. The dissociation constant (Kd) for the single site was 0.34 nM with a binding capacity of 2.25 fmol/10(7) cells. These data are in close agreement with data obtained from kinetic studies, in which the kinetically derived value of the dissociation constant was 0.20 nM. The affinity of these binding sites suggests that they may recognize the physiological concentrations of melatonin in serum. Moreover, pharmacological doses of melatonin also inhibited cyclic AMP production stimulated by forskolin, a potent activator of adenylate cyclase system. The demonstration of [125I]MEL binding sites in the spleen, in addition to those described in blood mononuclear cells and thymus, provides evidence to support a direct mechanism of action of melatonin on immune system.



Pineal-opioid system interactions in the control of immunoinflammatory responses.

Ann N Y Acad Sci (UNITED STATES) Nov 25 1994, 741 p191-6

Several studies have demonstrated involvement of the pineal gland in the regulation of neuropeptide secretion and activity. In particular, the existence of links between the pineal gland and the brain opioid system has been documented. Both opioid peptides and melatonin (MLT), the most investigated pineal hormone, play an important role in neuromodulation of the immunity. Moreover, the immune effects of MLT are mediated by endogenous opioid peptides, which may be produced by both the endocrine system and the immune cells. In addition, the immune dysfunctions that characterize some human diseases, such as cancer, depend not only on the immune system per se, but also at least in part, on altered secretion of immunomodulating neurohormones, including MLT and opioid peptides. Therefore, the exogenous administration of neurohormones could potentially improve the immune status in humans. The present study evaluates the effects of MLT on changes in the number of T lymphocytes, natural killer cells, and eosinophils induced by exogenous administration of interleukin-2 (IL-2). Macrophage activity was also evaluated by determining serum levels of its specific marker, neopterin. The study was performed in 90 patients with advanced solid neoplasms, who received IL-2 at a dose of 3 million IU/day subcutaneously for 6 days a week for 4 weeks plus MLT at a daily dose of 40 mg. Both drugs were given in the evening. The results were compared to those in 40 cancer patients treated with IL-2 alone. The mean increase in T lymphocytes, natural killer cells, and eosinophils was significantly higher in patients treated with IL-2 plus MLT than in those who received IL-2 alone.(ABSTRACT TRUNCATED AT 250 WORDS)



Evidence for a direct action of melatonin on the immune system.

Biol Signals (SWITZERLAND) Mar-Apr 1994, 3 (2) p107-17

Pineal melatonin modulates the mammalian immune system. In vivo studies showed that melatonin enhanced the natural and acquired immunity while in vitro studies demonstrated its inhibitory influence. The mechanism of melatonin action on the immune system remains unknown. Actions through lymphokines or opioid release or via other endocrine changes have been proposed. In this paper, a direct action of melatonin on the lymphoid tissue is hypothesized. 2-[125I]Iodomelatonin binding sites have been identified in the membrane homogenates of thymus, bursa of Fabricius and spleens of a number of birds and mammals. The bindings were stable, saturable, reversible, specific and of high affinity. The Bmax ranged from 0.6 to 3.9 fmol/mg protein. The Kd was in the physiological range of circulating melatonin levels, about 30-70 pmol/l. The binding sites in the primary lymphoid organs demonstrated diurnal variation in density, with higher levels found at the middle of the light period. However, those in the spleen did not vary with the time of the day. An age-dependent decrease in the density was also found in the chicken bursa of Fabricius. In addition, when the nocturnal melatonin secretion was suppressed by constant light exposure, the density of the binding sites increased in the guinea pig spleen. Immunosuppression with cortisol injection in young ducks decreased the density of the melatonin binding sites in the thymus. The regulation of the binding characteristics by physiological variation in melatonin levels and/or immunological status of the animals provide evidence that these 2-[125I]iodomelatonin binding sites in the lymphoid tissues may be physiologically significant and represent true melatonin receptors. The melatonin receptors in the lymphoid organs may be coupled to a G protein as Guanosine 5'-0-(3-thiotriphosphate inhibited 2-[125I]iodomelatonin binding in the spleen by increasing the Kd and decreasing the Bmax. (87 Refs.)



The immuno-reconstituting effect of melatonin or pineal grafting and its relation to zinc pool in aging mice.

J Neuroimmunol (NETHERLANDS) Sep 1994, 53 (2) p189-201

It has been demonstrated that melatonin, the main neuro-hormone of the pineal gland, affects thymic functions and the regulation of the immune system. In addition, experimental evidences indicate that melatonin can modulate zinc turnover. The knowledge that with advancing age both melatonin and zinc plasma levels decline, and that zinc supplementation in old mice is able to restore the reduced immunological functions, has prompted investigations on the effect of chronic melatonin treatment or pineal graft in old mice on the age-related decline of thymic endocrine activity, peripheral immune functions and zinc turnover. Both melatonin treatment in old mice and pineal graft into the thymus of old mice correct the reduced thymic endocrine activity and increase the weight of the thymus and its cellularity. A restoration of cortical thymic volume, as detected by the percentage of tissue in active proliferation, is also observed in old mice after both treatments. Thymocyte CD phenotype expression is also restored to young values. At peripheral level, recovery of peripheral blood lymphocyte number and of spleen cell subsets, with increased mitogen responsiveness also occurs. Melatonin treatment or pineal graft induce also a restoration of the altered zinc turnover in aged mice with an increment of the crude zinc balance from negative (-1.6 microgram/day/mouse) to positive value (+1.2 microgram/day/mouse), similar to that one of young mice (+1.4 microgram/day/mouse). The reduced zinc plasma level is restored to normal values. These findings support the idea that the effect of melatonin on thymic endocrine activity and peripheral immune functions may be mediated by the zinc pool.



Multiple sclerosis: the role of puberty and the pineal gland in its pathogenesis.

Int J Neurosci (ENGLAND) Feb 1993, 68 (3-4) p209-25

Epidemiological studies demonstrate that the incidence of multiple sclerosis (MS) is age-dependent being rare prior to age 10, unusual prior to age 15, with a peak in the mid 20s. It has been suggested that the manifestation of MS is dependent upon having passed through the pubertal period. In the present communication, I propose that critical changes in pineal melatonin secretion, which occur in temporal relationship to the onset of puberty, are intimately related to the timing of onset of the clinical manifestations of MS. Specifically, it is suggested that the fall in melatonin secretion during the prepubertal period, which may disrupt pineal-mediated immunomodulation, may stimulate either the reactivation of the infective agent or increase the susceptibility to infection during the pubertal period. Similarly, the rapid fall in melatonin secretion just prior to delivery may account for the frequent occurrence of relapse in MS patients during the postpartum period. In contrast, pregnancy, which is associated with high melatonin concentrations, is often accompanied by remission of symptoms. Thus, the presence of high melatonin levels may provide a protective effect, while a decline in melatonin secretion may increase the risk for the development and exacerbation of the disease. The melatonin hypothesis of MS may explain other epidemiological and clinical phenomena associated with the disease such as the low incidence of MS in the black African and American populations, the inverse correlation with sun light and geomagnetic field exposure, the occurrence of relapses in relation to seasonal changes and fluctuations in mood, and the association of MS with affective illness and malignant disease. Therapeutically, this hypothesis implies that application of bright light therapy or the use of other major synchronizers of circadian rhythms such as sleep deprivation or application of external weak magnetic fields may be beneficial in the treatment and/or prophylaxis of relapses in the disease. (174 Refs.)



Modulation of human lymphoblastoid interferon activity by melatonin in metastatic renal cell carcinoma. A phase II study.

Cancer (UNITED STATES) Jun 15 1994, 73 (12) p3015-9

BACKGROUND. Numerous attempts to identify active cytotoxic agents for the treatment of metastatic renal cell carcinoma (RCC) have proved disappointing. However, several recent developments in biologic therapy of neoplastic disease have substantially improved the prospects for the treatment of advanced RCC. Melatonin (MLT), a hormone regulated by the pineal gland, has been shown to act on the immune system by causing the release of cytokines from activated T-cell populations. METHODS. A series of 22 patients with documented progressing RCC entered a trial in which the authors studied the effect of a long term regimen (12 months) with human lymphoblastoid interferon (IFN), 3 mega units (MU) intramuscularly 3 times per week, and MLT, 10 mg orally every day. RESULTS. Twenty-one patients were evaluable for response and toxicity. There were seven remissions (33%): three complete, involving lung and soft tissue and four partial, with a median duration at the time of this writing of 16 months. Nine patients achieved stable disease, and five progressed. General toxicity was mild. Fever, chills, arthralgias, and myalgias occurred rarely. Leukopenia and hepatic enzyme elevation were modest and always reversible. CONCLUSIONS. Response rate and toxic effects observed during this study warrant additional randomized studies to define the role of MLT's concomitant administration in the clinical response to IFN in metastatic RCC.



Modulation of 2[125I]iodomelatonin binding sites in the guinea pig spleen by melatonin injection is dependent on the dose and period but not the time.

Life Sci (ENGLAND) 1994, 54 (19) p1441-8

Effects of dose, time and period of melatonin injection on 2[125I]iodomelatonin binding sites in the guinea pig spleen were studied. Guinea pigs (Dunkin-hartley), kept under 12h light/12 h darkness, were given daily intraperitoneal injections of either vehicle or 0.01, 0.1 or 1 mg melatonin/kg body weight in either early (1 hour after onset of light period) or late light period (1 hour before offset of light period) for 2 or 7 days. To study the effect of opioid antagonist on the binding, intraperitoneal injections of 2 or 20 mg naltrexone/kg body weight alone or together with 0.1 mg melatonin/kg body weight was given daily in late light period for 2 days. 2[125I]Iodomelatonin binding assays were performed on spleen membrane preparations and radioimmunoassays of melatonin levels were carried out in serum and pineal glands collected during mid-light. High dose (1 mg/kg body weight) of melatonin injection elevated the mid-light serum melatonin levels without affecting pineal melatonin levels. Early light injection group had a higher mid-light serum melatonin level. Melatonin injection for 2 days at either time points caused a dose-dependent decrease in Bmax and increase in Kd of 2[125I]iodomelatonin binding sites in the spleen. The response was independent of the time of injection. A greater suppression of binding was achieved by injecting melatonin for 7 days. Naltrexone did not affect the binding by itself and was not able to reverse the melatonin-induced suppression of binding in the spleen. The modulation of the splenic 2[125I]iodomelatonin binding sites by exogenous melatonin suggests that melatonin may act directly on the immune system to affect its function.



Binding of [125I]-labelled iodomelatonin in the duck thymus.

Biol Signals (SWITZERLAND) Sep-Oct 1992, 1 (5) p250-6

[125I]-labelled iodomelatonin binding sites in membrane preparations of duck thymus were studied. The specific binding of [125I]-labelled iodomelatonin in the duck thymus was stable, saturable, reversible and of high affinity. Scatchard analysis of the binding of [125I]-labelled iodomelatonin in the duck thymus collected at midlight had an equilibrium dissociation constant (Kd) of 34.8 +/- 9.4 pmol/l and a maximum number of binding sites (Bmax) of 0.98 +/- 0.07 fmol/mg protein. Two-point diurnal study demonstrated that the Bmax in samples collected at midlight was 42.0% higher (p < 0.05) than that at middark, but there was no significant difference (p > 0.05) between the midlight and middark Kd values. Competition inhibition studies showed that only melatonin, 2-iodomelatonin, 6-chloromelatonin, 6-hydroxymelatonin, N-acetylserotonin, 5-methoxytryptoph ol, and 5-hydroxytryptamine showed significant inhibition of the [125I]iodomelatonin binding in duck thymus membrane preparations, while the other compounds had no significant inhibition. Our results suggested a direct action of melatonin on the thymus and, thus, the cellular immune system.



Characteristics of 2-[125I]iodomelatonin binding sites in the pigeon spleen and modulation of binding by guanine nucleotides.

J Pineal Res (DENMARK) May 1993, 14 (4) p169-77

2-[125]Iodomelatonin binding sites in membrane preparations of pigeon spleen have been characterized. The binding was stable, saturable, reversible, and of high affinity. Rosenthal and Hill analyses showed that the radioligand-receptor interaction involved a single class of binding sites. Analysis of the binding results of spleens collected during mid-light revealed an equilibrium dissociation constant (Kd) of 36.6 +/- 4.8 pmol/l (mean +/- sem, n = 10) and a maximum density (Bmax) of 2.3 +/- 0.2 fmol/mg protein. There was no significant difference in the Kd (46.9 +/- 5.0 pmol/l) or the Bmax values (2.4 +/- 0.3 fmol/mg protein) for spleens collected during mid-dark (n = 9), although the mid-dark serum and pineal melatonin levels were significantly higher (P < 0.05) than the corresponding mid-light values. Kinetic analysis showed a Kd of 8.6 +/- 2.0 pmol/l (n +/- 4), in agreement with that derived from the saturation studies. Except for inhibition by 2-iodomelatonin, melatonin, 6-chloromelatonin, 6-hydroxymelatonin and N-acetylserotonin, the other indoles or neurotransmitters tested have little inhibition on the binding. In addition, guanosine 5'-O-(3-thiophosphate) (GTP gamma S), a nonhydrolysable analog of GTP, was found to inhibit the binding in a dose-dependent manner. Saturation studies revealed that this is due to a decrease in both the affinity and density of the binding sites. These data suggest that a single type of melatonin receptor is found in the pigeon spleen and that the site is coupled to a guinine nucleotide binding protein (G-protein). Our findings support a direct pineal melatonin action on the immune system.



Pinealectomy ameliorates collagen II-induced arthritis in mice.

Clin Exp Immunol (ENGLAND) Jun 1993, 92 (3) p432-6

To extend our previous findings that exposure to constant darkness (stimulation of endogenous melatonin release) as well as treatment with exogenous melatonin magnifies the severity of collagen-induced arthritis in mice, we have examined the effects of melatonin cutback by removing the pineal gland. Two strains of mice, DBA/1 and NFR/N, were subjected to surgical pinealectomy. The melatonin levels in sera were reduced by approximately 70% by the pinealectomy compared with the corresponding sham-operated controls. After 3-4 weeks of rest the mice were immunized with rat type II collagen to induce autoimmune arthritis, and the animals were kept in constant darkness during the experiments. In comparison with the controls, all groups of pinealectomized mice showed reduced severity of the arthritis by means of (i) a slower onset of the disease, (ii) a less severe course of the disease (reduced clinical scores), and (iii) reduced serum levels of anti-collagen II antibodies. These effects were not significant in all experiments, but the trends were always the same. Thus, the present result strengthen the hypothesis that high physiological levels of melatonin (which can be induced by exposure to darkness) stimulate the immune system and cause exacerbation of autoimmune collagen II arthritis, while inhibition of melatonin release (pinealectomy or exposure to light) has a beneficial effect.



2[125I]iodomelatonin binding sites in spleens of guinea pigs.

Life Sci (ENGLAND) 1992, 50 (22) p1719-26

2-[125I]Iodomelatonin was found to bind specifically to the membrane preparations of the spleens of guinea pigs with high affinity. The binding was rapid, stable, saturable and reversible. Scatchard analysis of the binding assays revealed an equilibrium dissociation constant (Kd) of 49.8 +/- 4.12 pmol/l and binding site density (Bmax) of 0.69 +/- 0.082 fmol/mg protein at mid-light (n = 10). There was no significant change in the Kd (41.8 +/- 3.16 pmol/l) or the Bmax (0.58 +/- 0.070 fmol/mg protein) at mid-dark (n = 10). Kinetic analysis showed a Kd of 23.13 +/- 4.81 pmol/l (mean +/- SE, n = 4), in agreement to that derived from the saturation studies. The 2-[125I]iodomelatonin binding sites have the following order of potency: 2-iodomelatonin greater than melatonin greater than 6-chloromelatonin much greater than N-acetylserotonin, 6-hydroxymelatonin greater than 5-methoxytryptamine, 5 methoxytryptophol greater than serotonin, 5-methoxyindole-3-acetic acid greater than 5-hydroxytryptophol, 3-acetylindole, 1-acetylindole-3-carboxyaldehyde, L-tryptophan greater than tryptamine, 5-hydroxyindole-3-acetic acid. Differential centrifugation studies showed that the binding sites are localized mainly in the nuclear fraction (65.5%), the rest are distributed in the microsomal fraction (17.4%), mitochondrial fraction (14.7%) and cytosolic fraction (0.3%). The demonstration of 2-[125I]iodomelatonin binding sites in the spleen suggests the presence of melatonin receptors and a direct mechanism of action of melatonin on the immune system.



Melatonin: a chronobiotic with anti-aging properties?

Med Hypotheses (ENGLAND) Apr 1991, 34 (4) p300-9

Recently, it has been reported that melatonin administration extends the lifespan of mice, a finding which supports previous research on the effects of pinealectomy and pineal extract administration. The prolongation of lifespan by melatonin has been interpreted in favour of an upregulation of the immune system as well as due to anti-stress properties of melatonin acting via the brain opioid system. In this paper we offer an alternative explanation of melatonin's anti-aging effect: the circadian pacemaker system has a diminished amplitude with age as indexed by a decrease in circulating melatonin levels. Stability of the circadian system correlates with its amplitude and loss of circadian amplitude produces lability which, in turn, leads to internal temporal disorder. Internal temporal disorder may be a precursor of disease states. Exogenous melatonin increases the amplitude of the circadian pacemaker system by feedback onto that system. The hypothalamic suprachiasmatic nuclei are thought to be the mammalian biological clock in the brain and have high concentrations of melatonin receptors. Therefore, melatonin administration in pharmacological doses may prevent aging symptoms by acting at the level of the circadian pacemaker's amplitude. (127 Refs.)



Effect of dose and time of melatonin injections on the diurnal rhythm of immunity in chicken.

J Pineal Res (DENMARK) Jan 1991, 10 (1) p30-5

The effect of daily melatonin injections on the diurnal rhythm of immune parameters was examined in White Leghorn cockerels, kept from hatching in L:D 12:12 conditions. Subcutaneous injections of melatonin were made at the beginning of darkness or 4 h earlier for four weeks starting from one week of life. The melatonin dosage in one group was raised (10, 13, 16, and 20 ng per bird daily, respectively) during four consecutive weeks. The two other doses were 10 and 500 times higher and were increased every week as well. Control birds received equivalent injections of vehicle. Three-week-old chickens were immunized ip with sheep red blood cells and reimmunized one week later. Five-week-old birds were sacrificed during a 24 h period every 4 h. The existence of the diurnal rhythm was evaluated by cosinor analysis. The diurnal rhythm of total white blood cells and serum agglutinins was more dependent on the time of melatonin injections than on the hormone used. The effect of melatonin injections on the level of immune parameters examined was also dependent on the time of sample collection. Results obtained indicate the participation of pineal gland in the regulation of the diurnal rhythm of the examined indices of avian immune system function that exhibit diurnal changes in sensitivity to exogenous melatonin.



The pineal neurohormone melatonin stimulates activated CD4+, Thy-1+ cells to release opioid agonist(s) with immunoenhancing and anti-stress properties.

J Neuroimmunol (NETHERLANDS) Jul 1990, 28 (2) p167-76

In previous studies we showed that in mice the pineal gland modulates the immune response via the circadian synthesis and release of melatonin. Exogenous melatonin proved also to exert immunoenhancing effects and to counteract completely the immunologic effect of acute stress. Melatonin was active only in vivo, in mice primed with T-dependent antigens and its effects on the primary antibody response and thymus weight were abolished by the specific opioid antagonist naltrexone. Here we demonstrate that physiologic concentrations of melatonin stimulate, in vitro, activated L3T4+ (CD4+) cells to release opioid agonist(s) that can reproduce in vivo the immunoenhancing and anti-stress effects on thymus cellularity and antibody production of melatonin and compete with specific binding of [3H]naloxone to mouse brain membranes. Similar results were obtained when mitogen-activated human immunocompetent cells were incubated with melatonin. In the human model the results were, however, less consistent than those obtained with murine cells, in that only four out of ten blood donors provided cells that were responsive to melatonin. This finding elucidates the mechanism of a novel immuno-neuroendocrine connection with relevant implications for our understanding of the neuroendocrine factors that may influence the immune response in vivo in normal and stressful situations. In addition, it opens new perspectives in a wide range of research fields.



Alterations of pineal gland and of T lymphocyte subsets in metastatic cancer patients: preliminary results.

J Biol Regul Homeost Agents (UNITED STATES) Oct-Dec 1989, 3 (4) p181-3

Melatonin (MLT), the main hormone produced by the pineal gland, has been seen to play a role in antineoplastic activity either by exerting a direct inhibitory effect on cancer cell growth, or by stimulating the immune system. Moreover, MLT blood levels have been shown to be often increased in cancer patients. On the basis of these data, a study was started to evaluate what relation exists between MLT levels and T lymphocyte subsets in patients with metastatic solid neoplasm. The study included 28 patients (breast: 10; non-small cell lung: 18). None of the patients was previously treated for their metastatic disease. Abnormally high MLT levels and a low T helper/suppressor ratio (CD4/CD8) were seen in 10/28 and in 11/28 patients, respectively. Serum mean levels of MLT were significantly higher in patients with low CD4/CD8 ratio than in those with a normal ratio. These results would suggest that immune dysfunctions may represent a signal for MLT release from the pineal in patients with metastatic solid neoplasm.



Endocrine and immune effects of melatonin therapy in metastatic cancer patients.

Eur J Cancer Clin Oncol (ENGLAND) May 1989, 25 (5) p789-95

Melatonin, the most important indole hormone produced by the pineal gland, appears to inhibit tumor growth; moreover, altered melatonin secretion has been reported in cancer patients. Despite these data, the possible use of melatonin in human neoplasms remains to be established. The aim of this clinical trial was to evaluate the therapeutic, immunological and endocrine effects of melatonin in patients with metastatic solid tumor, who did not respond to standard therapies. The study was carried out on 14 cancer patients (colon, six; lung, three; pancreas, two; liver, two; stomach, one). Melatonin was given intramuscularly at a daily dose of 20 mg at 3.00 p.m., followed by a maintenance period in an oral dose of 10 mg daily in patients who had a remission, stable disease or an improvement in PS. Before and after the first 2 months of therapy, GH, somatomedin-C, beta-endorphin, melatonin blood levels and lymphocyte subpopulations were evaluated. A partial response was achieved in one case with cancer of the pancreas, with a duration of 18+ months; moreover, six patients had stable disease, while the other eight progressed. An evident improvement in PS was obtained in 8/14 patients. In patients who did not progress, T4/T8 mean ratio was significantly higher after than before melatonin therapy, while it decreased in patients who progressed. On the contrary, hormonal levels were not affected by melatonin administration. This study would suggest that melatonin may be of value in untreatable metastatic cancer patients, particularly in improving their PS and quality of life; moreover, based on its effects on the immune system, melatonin could be tested in association with other antitumor treatments.



Melatonin modulation of estrogen-regulated proteins, growth factors, and proto-oncogenes in human breast cancer.

J Pineal Res (DENMARK) Mar 1995

The growth-inhibitory actions of the pineal hormone, melatonin, on human breast tumor cells and the possible association between this inhibition and melatonin's down-regulation of the estrogen receptor (ER) expression were examined in the ER-positive, estrogen-responsive MCF-7 human breast tumor cell line. As previously reported, melatonin dramatically inhibits the growth of these breast tumor cells and down-regulates ER levels in these cells, suggesting that the modulation of ER may be an important mechanism by which melatonin inhibits breast cancer cell growth. In the present studies, Northern blot analysis was used to examine the expression of estrogen-regulated transcripts known to be involved in estrogen's mitogenic actions. Melatonin, at a physiologic concentration (10(-9) M), rapidly, significantly, and, in some cases, transiently elevated the steady-state mRNA levels of growth stimulatory products such as TGF alpha, c-myc, and pS2, which are normally up-regulated in response to estrogen. Conversely, melatonin decreased the expression of other factors normally up-regulated by estrogen, such as progesterone receptor and c-fos. Significant stimulation of the expression of the growth-inhibitory factor TGF beta was seen with melatonin treatment, potentially supporting the concept that melatonin's growth-inhibitory activity is mediated through the breast tumor cells' estrogen-response pathway. The early regulation of many of these products by melatonin suggests that mechanisms more rapid than the down-regulation of ER are important in melatonin's modulation of their expression. However, the long-term modulation of these transcripts (12-48 hr) may be heavily influenced by melatonin's down-regulation of ER expression. These results clearly define the need for additional in depth studies to dissect the cellular events leading to melatonin-induced growth inhibition in breast tumor cells.



Melatonin inhibition of MCF-7 human breast-cancer cells growth: influence of cell proliferation rate.

Cancer Lett (IRELAND) Jul 13 1995

We have studied whether the cell proliferation rate modifies the inhibitory actions of melatonin on MCF-7 cell growth. The proliferative rate of cells was altered by plating them at different densities (5 x 10(4) to 100 x 10(4) cells/dish) in media with low charcoal-stripped serum concentrations. In this way, population doubling time ranged from 33 h (for density = 100 x 10(4) cells/dish) to 75 h (for density = 5 x 10(4) cells/dish). Melatonin (10(-9)M) only inhibited fast proliferating MCF-7 cells, increasing their cell doubling time, and did not significantly modify the length of doubling time in the cultures with low proliferation rate, in which doubling time was already long. These data clearly show that there is a direct relation between proliferative rate of cells and melatonin inhibitory actions on MCF-7 cells.



Modulation of cancer endocrine therapy by melatonin: a phase II study of tamoxifen plus melatonin in metastatic breast cancer patients progressing under tamoxifen alone.

Br J Cancer (ENGLAND) Apr 1995

Recent observations have shown that the pineal hormone melatonin (MLT) may modulate oestrogen receptor (ER) expression and inhibit breast cancer cell growth. On this basis, we have evaluated the biological and clinical effects of a concomitant MLT therapy in women with metastatic breast cancer who had progressed in response to tamoxifen (TMX) alone. The study included 14 patients with metastasis who did not respond (n = 3) to therapy with TMX alone or progressed after initial stable disease (SD) (n = 11). MLT was given orally at 20 mg day-1 in the evening, every day starting 7 days before TMX, which was given orally at 20 mg day-1 at noon. A partial response was achieved in 4/14 (28.5%) patients (median duration 8 months). The treatment was well tolerated in all cases, and no MLT-induced enhancement of TMX toxicity was seen; on the contrary, most patients experienced a relief of anxiety. Mean serum levels of insulin-like growth factor 1 (IGF-1), which is a growth factor for breast cancer, significantly decreased on therapy, and this decline was significantly higher in responders than in patients with SD or progression. This pilot phase II study would suggest that the concomitant administration of the pineal hormone MLT may induce objective tumour regressions in metastatic breast cancer patients refractory to TMX alone.



Modulation of estrogen receptor mRNA expression by melatonin in MCF-7 human breast cancer cells.

Mol Endocrinol (UNITED STATES) Dec 1994

Melatonin, the hormonal product of the pineal gland, has been shown to inhibit the development of mammary tumors in vivo and the proliferation of MCF-7 human breast cancer cells in vitro by mechanisms not yet identified. However, previous studies have demonstrated that melatonin significantly decreased estrogen-binding activity and the expression of immunoreactive estrogen receptor (ER) in MCF-7 breast cancer cells. To determine the mechanism(s) by which melatonin regulates ER expression in MCF-7 cells, the relationship between the level of steady state ER mRNA and the rate of ER gene transcription were examined in response to melatonin. Physiological concentrations of melatonin decreased steady state levels of ER mRNA expression in a dose- and time-specific manner. This decrease was not dependent upon the presence of estrogen since similar decreases in steady state ER mRNA levels were seen in MCF-7 cells cultured in both complete and estrogen-depleted media. The decreased expression of ER mRNA in response to melatonin appears to be directly related to the suppression of transcription of the ER gene. This regulation is independent of the synthesis of new proteins, as cycloheximide was unable to block the melatonin-induced decrease of steady-state ER mRNA levels. The down-regulation of ER by melatonin appears to not be mediated via a direct interaction with the ER and subsequent feedback on its own expression, since melatonin treatment did not alter the transcriptional regulatory ability of the fully activated wild type ER or a constitutively active hormone-binding domain-deleted ER variant. In addition, the stability of the ER transcript was unaffected by melatonin. Thus, it appears that the antiproliferative actions of this pineal indoleamine are mediated, at least in part, through the suppression of the transcription of the ER gene in MCF-7 human breast cancer cells.



Melatonin modulates growth factor activity in MCF-7 human breast cancer cells.

J Pineal Res (DENMARK) Aug 1994

Melatonin has been shown to have direct oncostatic actions on estrogen-responsive, MCF-7 human breast cancer cells in culture. In the present study, we examined whether these inhibitory actions on cell growth may be mediated through actions on bioassayable growth factor activity. In order to test this hypothesis, we estimated the growth factor activity of conditioned medium (CM) from estradiol (E2), or melatonin-treated cells, in the presence or absence of melatonin on MCF-7 cell growth. We also determined whether melatonin inhibits the action of epidermal growth factor (EGF) action in the absence of E2. The addition of melatonin (10(-9) M) to the cultures of MCF-7 cells with CM from E2 (10(-8) M)-treated cells significantly inhibited the growth stimulatory activity of CM, suggesting that melatonin inhibited cell proliferation by blocking the action of E2-induced autocrine growth stimulatory factors. Conditioned medium from melatonin-treated cells significantly inhibited cell proliferation, while an additional supply of melatonin to these cultures had an even greater inhibitory effect. Melatonin was also active in the complete absence of serum as long as cell growth was stimulated by EGF, an E2-inducible growth factor. The inhibitory effect of melatonin increased as the dose of EGF increased. This non-antiestrogenic inhibitory effect of melatonin was reversed by E2, but not by EGF itself, suggesting that melatonin requires accessible estrogen receptor sites for its inhibitory activity on the growth stimulating action of EGF. Taken together, these findings suggest that melatonin may inhibit the action and/or release of growth stimulatory factors as well as stimulate the release of growth inhibitory factors in culture.



Role of pineal gland in aetiology and treatment of breast cancer.

Lancet (ENGLAND) Oct 14 1978

The hypothesis that diminished function of the pineal gland may promote the development of breast cancer in human beings is suggested by the relation between breast cancer and prolonged oestrogen excess, and by the observation that the pineal secretion, melatonin, inhibits ovarian oestrogen production, pituitary gonadotrophin production, and sexual development and maturation. The hypothesis is supported by the following points. (1) Pineal calcification is commonest in countries with high rates of breast cancer and lowest in areas with a low incidence; the incidences of pineal calcification and of breast cancer are moderate among the black population in the United States. (2) Chlorpromazine raises serum-melatonin; there are reports that psychiatric patients taking chlorpromazine have a lower incidence of breast cancer. (3) Although information is lacking on breast cancer, the pineal and melatonin may influence tumour induction and growth in experimental animals. (4) The demonstration of a melatonin receptor in human ovary suggests a direct influence of this hormone on the ovarian function, and possibly oestrogen production. (5) Impaired pineal secretion is believed to be an important factor triggering puberty (early menarche is a risk factor for breast cancer).



A review of the evidence supporting melatonin's role as an antioxidant.

J Pineal Res (DENMARK) Jan 1995, 18 (1) p1-11

This survey summarizes the findings, accumulated within the last 2 years, concerning melatonin's role in defending against toxic free radicals. Free radicals are chemical constituents that have an unpaired electron in their outer orbital and, because of this feature, are highly reactive. Inspired oxygen, which sustains life, also is harmful because up to 5% of the oxygen (O2) taken in is converted to oxygen-free radicals. The addition of a single electron to O2 produces the superoxide anion radical (O2-.); O2-. is catalytic-reduced by superoxide dismutase, to hydrogen peroxide (H2O2). Although H2O2 is not itself a free radical, it can be toxic at high concentrations and, more importantly, it can be reduced to the hydroxyl radical (.OH). The .OH is the most toxic of the oxygen-based radicals and it wreaks havoc within cells, particularly with macromolecules. In recent in vitro studies, melatonin was shown to be a very efficient neutralizer of the .OH; indeed, in the system used to test its free radical scavenging ability it was found to be significantly more effective than the well known antioxidant, glutathione (GSH), in doing so. Likewise, melatonin has been shown to stimulate glutathione peroxidase (GSH-Px) activity in neural tissue; GSH-PX metabolizes reduced glutathione to its oxidized form and in doing so it converts H2O2 to H2O, thereby reducing generation of the .OH by eliminating its precursor. More recent studies have shown that melatonin is also a more efficient scavenger of the peroxyl radical than is vitamin E. The peroxyl radical is generated during lipid peroxidation and propagates the chain reaction that leads to massive lipid destruction in cell membranes. In vivo studies have demonstrated that melatonin is remarkably potent in protecting against free radical damage induced by a variety of means. Thus, DNA damage resulting from either the exposure of animals to the chemical carcinogen safrole or to ionizing radiation is markedlyreduced when melatonin is co-administered. Likewise, the induction of cataracts, generally accepted as being a consequence of free radical attack on lenticular macromolecules, in newborn rats injected with a GSH-depleting drug are prevented when the animals are given daily melatonin injections. Also, paraquat-induced lipid peroxidation in the lungs of rats is overcome when they also receive melatonin during the exposure period. Paraquat is a highly toxic herbicide that inflicts at least part of its damage by generating free radicals.



Treatment of cancer chemotherapy-induced toxicity with the pineal hormone melatonin.

Support Care Cancer (GERMANY) Mar 1997, 5 (2) p126-9

Experimental data have suggested that the pineal hormone melatonin (MLT) may counteract chemotherapy-induced myelosuppression and immunosuppression. In addition, MLT has been shown to inhibit the production of free radicals, which play a part in mediating the toxicity of chemotherapy. A study was therefore performed in an attempt to evaluate the influence of MLT on chemotherapy toxicity. The study involved 80 patients with metastatic solid tumors who were in poor clinical condition (lung cancer: 35; breast cancer: 31; gastrointestinal tract tumors: 14). Lung cancer patients were treated with cisplatin and etoposide, breast cancer patients with mitoxantrone, and gastrointestinal tract tumor patients with 5-fluorouracil plus folates. Patients were randomised to receive chemotherapy alone or chemotherapy plus MLT (20 mg/day p.o. in the evening). Thrombocytopenia was significantly less frequent in patients concomitantly treated with MLT. Malaise and asthenia were also significantly less frequent in patients receiving MLT. Finally, stomatitis and neuropathy were less frequent in the MLT group, albeit without statistically significant differences. Alopecia and vomiting were not influenced by MLT. This pilot study seems to suggest that the concomitant administration of the pineal hormone MLT during chemotherapy may prevent some chemotherapy-induced side-effects, particularly myelosuppression and neuropathy. Evaluation of the impact of MLT on chemotherapy efficacy will be the aim of future clinical investigations.



Treatment of cancer-related thrombocytopenia by low-dose subcutaneous Interleukin-2 plus the pineal hormone melatonin: A biological phase II study

Journal of Biological Regulators and Homeostatic Agents (Italy), 1995, 9/2 (52-54)

Despite the platelet production in response to IL-2, cancer immunotherapy with IL-2 tends to induce thrombocytopenia, which probably depends on an enhanced peripheral destruction. On the basis of our previous studies, this effect may be neutralized by a concomitant administration of the pineal hormone melatonin (MLT). This study was performed to investigate the influence of an immunotherapeutic combination with low-dose IL-2 and MLT on platelet number in advanced cancer patients showing persistent thrombocytopenia. The study included 14 advanced solid tumor patients, affected by thrombocytopenia due to different causes (portal hypertension: 9; previous chemotherapies: 3; DIC: 2). IL-2 was injected at 3 million IU/day subcutaneously for 6 days/week for 4 weeks, in association with MLT (40 mg/day orally). A normalization of platelet number occurred in 10/14 (71%) patients, and platelet mean number significantly increased on treatment. No important therapy-related toxicity was observed This preliminary study would suggest that the concomitant administration of MLT is able not only to neutralize IL-2-induced thrombocytopenia, but also to increase platelet number in thrombocytopenic cancer patients.



Type 2 Th cells as target of the circadian melatonin signal: Relevance in local immunity

Regional Immunology (USA), 1995, 6/5-6 (350-354)

In previous work we have shown that melatonin can augment the immune response and correct immunodeficiency states which may follow acute stress, viral diseases, aging, or drug treatment via T-cell cytokines. In addition, we have demonstrated that the combination of melatonin with low-dose interleukin-2 (IL2) represents a well-tolerated strategy capable of inducing tumor regression in cancer patients. Here, we review our last studies which revealed the existence of a melatonin-Th2 cytokine network. Melatonin did not influence tumor growth but selectively counteracted bone marrow toxicity when administered together with cancer chemotherapy compounds without interfering with their anticancer action. In vitro, melatonin proved to counteract apoptosis in bone-marrow cells incubated with etoposide. The effect of melatonin was neutralized by anti-granulocyte-macrophage colony-stimulating factor (anti-GM-CSF) monoclonal antibodies. In addition, when added at physiological concentrations in the granulocyte-macrophage colony-forming units (GM-CFU) assay in presence of suboptimal concentrations of GM-CSF, melatonin was able to augment the number of GM-CFU. When bone marrow from athymic, T cell-deficient mice or CD4+, T helper cells-depleted marrow was used, melatonin did not exert any effect. This suggested that melatonin is able to stimulate the endogenous production of GM-CSF via bone marrow T cells. Further studies revealed that melatonin acts on Th2 cells inducing, both at physiological and pharmacological concentrations, the release of IL4. In turn, IL4 stimulates the production of GM-CSF by adherent bone marrow cells. A modulation of the production of endogenous cytokines is likely to present substantial advantages over systemic administration. Due to the well- known lack of toxicity of melatonin, our finding may thus have straightforward clinical applications, which may range from hematopoietic rescue to cancer immunotherapy. Last but not least, our findings demonstrate the existence of a basic environmental influence on IL4 production which might have several implications in regional immunology.



Hematopoietic rescue via T-cell-dependent, endogenous granulocyte- macrophage colony-stimulating factor induced by the pineal neurohormone melatonin in tumor-bearing mice

CANCER RES. (USA), 1994, 54/9 (2429-2432)

We investigated whether melatonin can affect tumor growth and/or hematopoiesis in mice transplanted with Lewis lung carcinoma and treated with cyclophosphamide or etoposide. These agents were injected i.p. for 5 days at two different cumulative doses (cyclophosphamide, 40 and 160 mg/kg body weight; etoposide, 20 and 40 mg/kg body weight) from day 8 through day 12 after tumor transplantation. Melatonin was injected s.c. at a dose of 1 mg/kg body weight/day, from day 8 throughout the experiments and from days 8 through 12 or from day 13 onwards. Melatonin did not influence tumor growth but selectively counteracted bone marrow toxicity when administered together with the cancer chemotherapy compounds without interfering with their anticancer action. In vitro, melatonin proved to counteract apoptosis in bone marrow cells incubated with etoposide. Such protection was reflected by an increased frequency of granulocyte/macrophage-colony forming units but not of the pluripotent spleen-colony forming units. The effect of melatonin was neutralized by anti-granulocyte/macrophage-colony-s timulating factor monoclonal antibodies. When athymic, T-cell-deficient mice were used as bone marrow donors, melatonin did not exert any protective effect. This suggested that melatonin is able to stimulate the endogenous production of granulocyte/macrophage-colony-stimulating factor via bone marrow T-cells. Due to the well known lack of toxic and undesirable side effects of melatonin, these findings might have a straightforward clinical application.



Randomized study with the pineal hormone melatonin versus supportive care alone in advanced nonsmall cell lung cancer resistant to a first-line chemotherapy containing cisplatin

ONCOLOGY (SWITZERLAND) (Switzerland), 1992, 49/5 (336-339)

At present, there is no effective medical therapy in metastatic nonsmall cell (NSC) lung cancer patients who progressed under a first-line chemotherapy containing cisplatin. Since recent data have demonstrated the antineoplastic properties and the lack of toxicity of the pineal hormone melatonin (MLT), a randomized study was designed to evaluate the influence of an MLT treatment (10 mg/day orally at 7.00 p.m.) on the survival time at 1 year from the progression under chemotherapy in respect to supportive care alone in a group of metastatic NSC lung cancer patients, who did not respond to a first-line chemotherapy containing cisplatin. The study includes 63 consecutive metastatic NSC lung cancer patients, who were randomized to receive MLT (n = 31) or supportive care alone (n = 32). The percentage of both stabilizations of disease and survival at 1 year was significantly higher in patients treated with MLT than in those treated only with supportive care. No drug-related toxicity was seen in patients treated with MLT, who, on the contrary, showed a significant improvement in performance status. This randomized study shows that the pineal hormone MLT may be successfully administered to prolong the survival time in metastatic NSC lung cancer patients who progressed under a first-line chemotherapy with cisplatin, for whom no other effective therapy is available up to now.



Melatonin increase as predictor for tumor objective response to chemotherapy in advanced cancer patients

TUMORI (Italy), 1988, 74/3 (339-345)

Clinical studies have demonstrated an altered pineal function in cancer patients. Owing to the documented antineoplastic activity of the pineal gland, these anomalies could have a prognostic significance. This study was carried out to monitor changes in blood levels of melatonin, the most important pineal hormone, in relation to the clinical response to chemotherapy in human neoplasms. The study included 42 cancer patients of both sexes (breast cancer, 10; lung cancer, 13; colon cancer, 11; soft tissue sarcoma, 4; testicular cancer, 1; Hodgkin's disease, 1; peritoneal mesothelioma, 2). Melatonin serum levels were measured by radioimmunoassay before and 28 days after each cycle of chemotherapy. The results showed that, irrespectively of the type of tumor and chemotherapeutic regimen, 12/16 patients (75%) whose melatonin markedly enhanced after chemotherapy had an objective regression. In contrast, 2/26 patients only (8%) whose melatonin did not enhance after chemotherapy had a clinical response. The percentage of objective responses was statistically significantly higher in patients with a chemotherapy-induced melatonin increase than in those with no melatonin increase (p < 0.001). This study seems to demonstrate that melatonin determination can be used as a predictor of the objective response to chemotherapy in cancer patients. Moreover, it suggests that the antineoplastic effect of cytotoxic drugs may require participation of the pineal gland.



Modulation of the length of the cell cycle of the MCF-7 human breast cancer cells by melatonin

Life Sciences (USA), 1996, 58/9 (811-816)

It has been shown that melatonin has a direct inhibitory effect on the proliferation of MCF-7 human breast cancer cells in culture. In the present work, we studied whether the length of the cell cycle of MCF-7 cells is increased by melatonin. In MCF-7 cells partially synchronized and labelled with (3H)thymidine, melatonin (109M), added to the culture medium, shifted the period of the labeling index rhythm from 20.36 hours to 23.48 hours. The fact that melatonin significantly increased (p < 0.005) the duration of the cell cycle of human breast cancer cells, support the notion that this hormone exerts part of its antitumor effect through a cell-cycle-specific mechanism by delaying the entry of MCF-7 cells into mitosis.



Melatonin blocks the stimulatory effects of prolactin on human breast cancer cell growth in culture.

Br J Cancer (ENGLAND) Dec 1995

Melatonin (aMT) appears to be a potentially important oncostatic substance that can block the mitogenic effects of tumour-promoting hormones and growth factors such as oestradiol and epidermal growth factor, in vitro. In the present study, we examined the possibility that aMT would also inhibit the stimulatory effects of the tumour-promoter prolactin (PRL) on MCF-7 and ZR75-1 human breast cancer cell (HBC) growth under 5% charcoal-stripped fetal bovine serum culture conditions. Human PRL (10-100 ng ml-1) stimulated the rate of MCF-7 and ZR-75-1 HBC growth up to 2-fold above that of untreated controls. Melatonin, at concentrations between 10(-12) M and 10(-5)M, diminished and at physiological levels completely abolished PRL's mitogenic activity, but had no effect on growth in the absence of PRL. The mitogenic effects of human growth hormone (hGH), a PRL-related hormone, and also of several monoclonal antibodies (Mabs) against the PRL receptor (PRLR), were also abrogated by physiological concentrations of aMT. Additionally, aMT blocked the enhancement of Mab mitogenic activity induced by a second 'cross-linking' antibody (CLA). These findings indicate that aMT interrupts the PRLR-mediated growth signal in HBC and suggest that the oncostatic activity of aMT may also be linked with an antagonism of PRL's actions.



Differences between pulsatile or continuous exposure to melatonin on MCF-7 human breast cancer cell proliferation.

Cancer Lett (IRELAND) Sep 30 1994

We studied the different in vitro antiproliferative actions of melatonin on MCF-7 cells, depending on whether the cells are exposed to hormone concentrations which remain constant in culture media (Group I, 10(-9) M; Group II, 10(-11) M melatonin) or varying at 12 h intervals, thus simulating a diurnal rhythm: Group III, 12 h in 10(-9) M melatonin/12 h without melatonin (10(-9) M/0 12/12 h); Group IV, 10(-11) M/0 12/12 h; Group V, 10(-9) M/10(-11) M 12/12 h. After 5 days of culture, cell proliferation appeared significantly inhibited in Groups I and III, but not in Groups II and IV. However, the highest antiproliferative effect was obtained by sequential exposure to 10(-9) M/10(-11) M melatonin (Group V), which mimics the physiological rhythm of serum melatonin concentration.



Effects of melatonin on cancer: studies on MCF-7 human breast cancer cells in culture.

J Neural Transm Suppl (AUSTRIA) 1986, 21 p433-49

There is some evidence to suggest that the pineal gland influences neoplastic growth. Either crude or partially-purified pineal extracts have been used to treat malignant neoplasms in humans. More compelling evidence indicates that the pineal hormone melatonin, in addition to its well known antireproductive effects, may also exert oncostatic effects particularly in animal models of human breast cancer. However, it is not clear whether melatonin inhibits mammary cancer growth via an indirect neuroendocrine mechanism or via an action directly on the cancer cells themselves. Studies are described in which physiological concentrations of melatonin are shown to have marked inhibitory effects directly on MCF-7 human breast cancer cell growth in culture. Supra- or subphysiological levels of melatonin are completely ineffective in retarding breast cancer cell proliferation. Precursors and metabolites of melatonin such as serotonin, N-acetylserotonin and 6-hydroxymelatonin do not inhibit MCF-7 cell growth. Similarly, neither 5-methoxytryptophol nor 5-methoxytryptamine, regarded by some to be putative pineal hormones, exhibit antimitogenic properties. Melatonin completely blocks the estradiol-induced stimulation of MCF-7 cell proliferation. In defined, serum-free medium, melatonin loses its antimitogenic capabilities unless cells are also simultaneously exposed to either estradiol or prolactin. Therefore, the antiproliferative effect of melatonin may be dependent on the presence of serum and a complex interaction with hormones such as estradiol and/or prolactin.



Neuroimmunotherapy of advanced solid neoplasms with single evening subcutaneous injection of low-dose interleukin-2 and melatonin: preliminary results.

Eur J Cancer (ENGLAND) 1993, 29A (2)

On the basis of the demonstrated existence of immunoneuroendocrine interactions and on the previously observed synergistic action between the pineal hormone melatonin (MLT) and interleukin-2 (IL-2), we have designed a neuroimmunotherapeutic combination consisting of low-dose IL-2 and MLT in the treatment of advanced solid neoplasms. The study included 24 patients with advanced solid tumours (non-small cell lung cancer 9; colorectal cancer 7; gastric cancer 3; breast cancer 2; cancer of pancreas 1; hepatocarcinoma 1; unknown primary tumour 1), 21 of whom showed distant organ metastases. Not all patients responded to previous chemotherapies, or had tumours for which no standard therapy was available. Moreover, not all patients were able to tolerate IL-2 immunotherapy at the conventional doses. IL-2 was given subcutaneously at a dose of 3 x 10(6) U/day at 8:00 p.m. for 6 days/week for 4 weeks. MLT was given orally at a dose of 50 mg at 8:00 p.m. every day, starting 7 days before IL-2 injection. In non-progressed patients, a second cycle was given after a 21-day rest period. A partial response was seen in 3/24 patients (lung 2; stomach 1; duration: 11, 4, 4 months, respectively). Moreover, a minimal response (duration: 8+ months) was seen in 1 lung cancer patient. Stable disease was obtained in 14/24 patients (median duration: 6+ months), while the remaining 6 patients progressed. An improvement in performance status was seen in 7/24 patients. No important toxicity was observed. Mean eosinophil and lymphocyte levels significantly increased during the immunotherapy, and their rise was significantly higher in patients with response or stable disease than in those with progressive disease. These preliminary results show that neuroimmunotherapy with low-dose IL-2 and the pineal hormone MLT is a biologically active and well tolerated strategy, capable of determining an apparent control of tumour growth in patients with advanced solid neoplasms, for whom no standard effective therapy is available.



Tissue changes in glutathione metabolism and lipid peroxidation induced by swimming are partially prevented by melatonin

Pharmacology and Toxicology (Denmark), 1996, 78/5 (308-312)

The present study used male Sprague-Dawley rats to investigate changes in glutathione (reduced (GSH) and oxidized GSH (GSSG)), lipid peroxidation (as indicated by tissue levels of malonaldehyde and 4-hydroxyalkenals), and the activity of the antioxidant enzyme glutathione peroxidase after a bout of swimming (30 min.) with or without melatonin (N-acetyl-5-methoxytryptamine) treatment. In muscle, the concentration of GSH and the GSH/GSSG ratio were decreased following 30 min. of swimming; these changes are indicative of enhanced oxidative stress. Pretreatment with melatonin prevented these effects. In liver, swimming increased significantly both GSH and GSSG, and decreased the GSH/GSSG ratio. When animals were treated with melatonin, concentrations of GSH and GSSG were also increased after swimming; however, the reduction in the GSH/GSSG ratio was prevented by melatonin. Brain GSH/GSSG ratio was not affected by exercise or by melatonin. Swimming enhanced the levels of lipid peroxidation products is muscle; this was prevented in animals treated with melatonin. Glutathione peroxidase activity was significantly elevated after swimming in both liver and brain with the change not being influenced by concurrent melatonin treatment. It is concluded that swimming imposes an oxidative stress on liver and skeletal muscle and the results show that melatonin confers partial protection against oxidative toxicity, especially in muscle.



Modulation of tumor necrosis factor-alpha (TNF-alpha) toxicity by the pineal hormone melatonin (MLT) in metastatic solid tumor patients

Annals of the New York Academy of Sciences (USA), 1995, 768 (334-336)

Treatment of cancer-related thrombocytopenia by low-dose subcutaneous interleukin-2 plus the pineal hormone melatonin: A biological phase II studyLissoni P.; Barni S.; Brivio F.; Rossini E.; Fumagalli L.; Tancini G.Divisione di Radioterapia, Ospedale S. Gerardo, 20052 Monza ItalyJournal of Biological Regulators and Homeostatic Agents (Italy), 1995, Despite the platelet production in response to IL-2, cancer immunotherapy with IL-2 tends to induce thrombocytopenia, which probably depends on an enhanced peripheral destruction. On the basis of our previous studies, this effect may be neutralized by a concomitant administration of the pineal hormone melatonin (MLT). This study was performed to investigate the influence of an immunotherapeutic combination with low-dose IL-2 and MLT on platelet number in advanced cancer patients showing persistent thrombocytopenia. The study included 14 advanced solid tumor patients, affected by thrombocytopenia due to different causes (portal hypertension: 9; previous chemotherapies: 3; DIC: 2). IL-2 was injected at 3 million IU/day subcutaneously for 6 days/week for 4 weeks, in association with MLT (40 mg/day orally). A normalization of platelet number occurred in 10/14 (71%) patients, and platelet mean number significantly increased on treatment. No important therapy-related toxicity was observed This preliminary study would suggest that the concomitant administration of MLT is able not only to neutralize IL-2-induced thrombocytopenia, but also to increase platelet number in thrombocytopenic cancer patients.



A biological study on the efficacy of low-dose subcutaneous interleukin-2 plus melatonin in the treatment of cancer-related thrombocytopenia.

Oncology (SWITZERLAND) Sep-Oct 1995, 52 (5) p360-2

The production of cytokines involved in platelet generation, including interleukin (IL)-3, IL-6 and IL-11, is stimulated by IL-2. However, the platelet number has been shown to decrease on IL-2 cancer therapy, and this side effect depends on the enhanced peripheral platelet destruction following the activation of the macrophage system by IL-2 itself. Our previous studies showed that IL-2-induced macrophage activation may be counteracted by the pineal hormone melatonin (MLT). On this basis, a pilotstudy with IL-2 plus MLT was performed to evaluate its influence on the platelet number in cancer patients with persistent thrombocytopenia. The study included 20 advanced solid tumor patients, who received IL-2 at 3 million IU/day s.c. for 6 days/week for 4 weeks in association with MLT (40 mg/day orally). A normalization of the platelet number was achieved in 14/20 (70%) patients. This pilot study shows that the therapy with low-dose IL-2 plus MLT, in addition to its previously described antitumor activity, may also be effective in the treatment of cancer-related thrombocytopenia.



Melatonin prevents death of neuroblastoma cells exposed to the Alzheimer amyloid peptide.

J Neurosci (UNITED STATES) Mar 1 1997, 17 (5) p1683-90

Studies from several laboratories have generated evidence suggesting that oxidative stress is involved in the pathogenesis of Alzheimer's disease (AD). The finding that the amyloid beta protein (Abeta) has neurotoxic properties and that such effects are, in part, mediated by free radicals has provided insights into mechanisms of cell death in AD and an avenue to explore new therapeutic approaches. In this study we demonstrate that melatonin, a pineal hormone with recently established antioxidant properties, is remarkably effective in preventing death of cultured neuroblastoma cells as well as oxidative damage and intracellular Ca2+ increases induced by a cytotoxic fragment of Abeta. The effects of melatonin were extremely reproducible and corroborated by multiple quantitative methods, including cell viability studies by confocal laser microscopy, electron microscopy, and measurements of intracellular calcium levels. The importance of this finding is that, in contrast to conventional antioxidants, melatonin has a proposed physiological role in the aging process. Secretion levels of this hormone are decreased in aging and more severely reduced in AD. The reported phenomenon may be of therapeutic relevance in AD.



Daily rhythm of serum melatonin in patients with dementia of the degenerate type.

Brain Res (NETHERLANDS) Apr 22 1996, 717 (1-2) p154-9

The daily rhythm in serum melatonin levels was measured in patients with dementia of the degenerate type (Alzheimer's disease, Pick's disease and senile dementia of the Alzheimer type) by radioimmunoassay. Thirteen patients (age: 69.0 +/- 8.0 years, mean +/- S.D.) were studied. All patients were hospitalized at the time of the study and had a history of sleep-wake disturbances, nocturnal wandering and/or delirium. We also studied 13 age-matched healthy control subjects (control group 1), ten young adults (control group 2), and nine hospitalized patients without dementia (control group 3). Two subjects in the control groups showed no measurable changes in melatonin level throughout the day, while the other 30 control subjects exhibited a clear daily rhythm with the peak concentration occurring during the night. On the other hand, four out of the 13 patients with dementia did not show any melatonin rhythm. Two of the demented patients who did not exhibit melatonin rhythm displayed clinical symptoms of rhythm disorders. One out of the nine patients with melatonin rhythm presented with clinical symptoms, such as delirium and sleep-wake disturbance. Our results suggest that the probability of absent melatonin rhythm is higher in demented patients compared with subjects without dementia. However, a lack of melatonin rhythm is not always associated with symptomatic rhythm disorders. Since the melatonin rhythm reflects that of the suprachiasmatic nucleus, it follows that the SCN function of the patients having a history of rhythm disorders was not always severely damaged.



The mystery of Alzheimer's disease and its prevention by melatonin.

Med Hypotheses (ENGLAND) Oct 1995, 45 (4) p339-40

Preliminary observation suggested that a melatonin deficiency could cause Alzheimer's disease. New evidence reveals that: 1) a significant melatonin deficiency is common in the disease, 2) melatonin acts as a hydroxyl radical scavenger and 3) brain tissue mitochondria from Alzheimer's patients have damage consistent with hydroxyl radical injury.



Chrono-neuroendocrinological aspects of physiological aging and senile dementia.

Chronobiologia (ITALY) Jan-Jun 1994, 21 (1-2) p121-6

The circadian pattern of melatonin and cortisol secretion was evaluated in two groups of elderly subjects (aged 66-90 years), one with Alzheimer's type of multiinfarct dementia (n = 27) and the other without cognitive impairment (n = 16); 13 clinically healthy women aged 20 to 30 years were chosen as controls. All demented patients had severe mental impairment, corresponding to stage 6 of the Global Deterioration Scale. All subjects, either young or aged, were studied as in-patients and were well synchronized with respect to meal timing, diurnal activity and nocturnal rest. At the population mean cosinor analysis (Halberg, 1969) both melatonin and cortisol circadian rhythms reached statistical significance in the three groups of subjects. However, the melatonin circadian profile was clearly flattened in the two groups of elderly subjects by comparison with young controls, due to the selective impairment of melatonin nocturnal secretion. In both elderly groups, but particularly in demented patients, plasma cortisol levels were significantly higher by comparison to young controls, particularly at evening and night time. A significant direct relationship linked the subjects' age and the nadir values of plasma cortisol. Furthermore, the sensitivity of the hypothalamo-pituitary-adrenal axis to dexamethasone (DXM) suppression test (1 mg orally at 2300) was significantly reduced in both elderly groups, and especially in old demented patients, by comparison with young controls. Finally, plasma cortisol response to pulse i.v. injection of a small dose of synthetic corticotropin (Synacthen 2,500 ng) was significantly higher and more prolonged in old demented patients than in mentally healthy old subjects and in young controls.



A phase II study of tamoxifen plus melatonin in metastatic solid tumour patients

British Journal of Cancer (United Kingdom), 1996, 74/9 (1466-1468)

Preliminary data would suggest that the pineal hormone, melatonin (MLT), may enhance tamoxifen (TMX) anti-tumour efficacy. Both MLT and TMX have been used as single agents in the palliative treatment of metastatic neoplasms, other than the classical hormone-dependent tumours, without, however, any clear efficacy. On this basis, a phase II study with TMX plus MLT hits been performed in untreatable metastatic solid tumour patients. The study included 25 metastatic solid tumour patients other than breast cancer and prostate cancer (six unknown primary tumour; four melanoma; four uterine cervix carcinoma; five pancreatic cancer; three hepatocarcinoma; two ovarian cancer; one non-small-cell lung cancer), for whom no other effective standard therapy was available, because of poor clinical conditions, no response to previous chemotherapies and/or chemotherapy-resistant tumours. Both drugs were given orally every day until disease progression (TMX, 20 mg day-1 at noon; MLT, 20 mg day-1 in the evening). Three patients had a partial response (PR) (12%; 95% confidence limits 2-24%) (one cervix carcinoma; one melanoma; one unknown primary tumour). A stable disease (SD) was achieved in 13 other patients, whereas the remaining nine patients progressed. Performance status (PS) improved in 9/25 patients, whose median score increased from 50% to 70%. Finally, a survival longer than 1 year was observed in 7/25 (28%) patients. This phase II study would suggest that the neuroendocrine combination with TMX plus MLT may have some benefit in untreatable metastatic solid tumour patients, either in controlling cancer cell proliferation.

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