Life Extension Final Clerance Sale

PREGNENOLONE



Table of Contents
image Pregnenolone and dehydroepiandrosterone as precursors of native 7-hydroxylated metabolites which increase the immune response in mice.
image 3beta-hydroxysteroid dehydrogenase/isomerase and aromatase activity in primary cultures of developing zebra finch telencephalon: Dehydroepiandrosterone as substrate for synthesis of androstenedione and estrogens
image Changes in serum concentrations of conjugated and unconjugated steroids in 40- to 80-year-old men.
image Ovarian suppression with triptorelin and adrenal stimulation with adrenocorticotropin in functional hyperadrogenism: role of adrenal and ovarian cytochrome P450c17 alpha.
image Memory-enhancing effects in male mice of pregnenolone and steroids metabolically derived from it.

bar

Pregnenolone and dehydroepiandrosterone as precursors of native 7-hydroxylated metabolites which increase the immune response in mice.

J Steroid Biochem Mol Biol (ENGLAND) Jul 1994, 50 (1-2) p91-100

Dehydroepiandrosterone (DHEA) and pregnenolone (PREG) were both metabolized by homogenates of brain, spleen, thymus, perianal skin, ventral skin, intestine, colon, coecum and muscle tissues from mice. The use of 2H-labeled substrates and of the twin ion technique of gas chromatography-mass spectrometry permitted identification of 7 alpha-hydroxy-DHEA and of 5-androstene-3 beta, 17 beta-diol as DHEA metabolites in digests of all tissues. The extent of PREG metabolism was much lower than for DHEA with all tissues but amounts of the main transformation product were sufficient in brain, spleen and ventral skin digests for identification with 7 alpha-hydroxy-PREG. Dimethylsulfoxide (DMSO) solutions of DHEA, PREG and of their 7-hydroxylated metabolites were injected at different doses and time intervals prior to proximal subcutaneous administration of a lysozyme antigen. Quantities of anti-lysozyme IgG were measured in the serum of treated mice and compared with that from sham-treated animals. Increase of anti-lysozyme IgG was obtained with DHEA and PREG (1 g/kg) when injected 2 h prior to lysozyme. Much lower doses (160 times less) of 7 alpha-hydroxy-DHEA and -PREG were also found to be significantly active when administered at the moment of lysozyme injection. A larger dose of 7 beta-hydroxy-DHEA (50 mg/kg) was necessary for a similar effect. These results suggest that in tissues where immune response takes place, the locally-produced 7-hydroxy metabolites of PREG and DHEA are involved in a process which may participate in the physiological regulation of the body's immune response.



3beta-hydroxysteroid dehydrogenase/isomerase and aromatase activity in primary cultures of developing zebra finch telencephalon: Dehydroepiandrosterone as substrate for synthesis of androstenedione and estrogens

General and Comparative Endocrinology (USA), 1996, 102/3 (342-350)

3beta-hydroxysteroid dehydrogenase/Deltleft arrow over right arrow-Delta4 isomerase (3beta-HSD) activity was measured in primary dissociated cell cultures prepared from telencephalons of developing zebra finches. 3beta-HSD activity was confirmed after cultures were incubated with (7-3H)pregnenolone (Preg) or (1,2,6,7- 3H-) dehydroepiandrosterone (DHEA) and 3H-progesterone (Prog) and 3H- androstenedione (AE) were detected in the medium. Product identity was confirmed by recrystallizations and by HPLC analysis. When DHEA was used as substrate, 3H-estradiol and 3H-estrone were also detected in the culture medium, presumably derived from the aromatization of 3H-AE or 3H-T produced from 3H-DHEA. To test this idea, cultures were incubated with 3H-DHEA together with radioinert AE or with fadrozole HCl, a potent and specific aromatase inhibitor. In the presence of radioinert AE, 3H-AE increased but metabolites of 3H-AE decreased in the media; in the presence of fadrozole, 3H-estrogens decreased but 3H-AE and its androgenic metabolite 3H-5beta- androstanedione increased. These data demonstrate 3beta-HSD activity in the songbird brain. The presence of Prog and estradiol in these cultures suggest that Preg and DHEA can potentially serve as substrates for the ultimate formation of active sex steroids in the songbird telencephalon.



Changes in serum concentrations of conjugated and unconjugated steroids in 40- to 80-year-old men.

J Clin Endocrinol Metab (UNITED STATES) Oct 1994, 79 (4) p1086-90

It is well recognized that aging in men is accompanied by a decline in the serum levels of some adrenal and testicular steroids, but little or no attention has focused on the multiple steroid metabolites that are formed by steroid-converting enzymes in target tissues. In the present study, we have examined in detail the serum concentrations of a large series of adrenal and testicular steroids and their most significant metabolites produced in intracrine peripheral tissues. The serum concentrations of 26 conjugated and unconjugated C21-, C19-, and C18-steroids were measured in 2423 men aged 40-80 yr. The serum concentrations of the major circulating adrenal C19-steroids, namely dehydroepiandrosterone (DHEA) and its sulfate (DHEA-S), androst-5-ene-3 beta, 17 beta-diol and its sulfate, and androstenedione, decreased by about 60% between the ages of 40-80 yr. The small decrease in the serum concentrations of progesterone and pregnenolone in the presence of increased levels of cortisol and markedly decreased levels of DHEA, androst-5-ene-3 beta, 17 beta-diol, and their polar metabolites suggests that adrenal 17,20-lyase is particularly affected by aging. In addition to a marked decline in the serum concentrations of adrenal C19-steroids, a smaller, but significant, decrease occurred in serum testosterone. However, serum dihydrotestosterone levels remained constant, but the glucuronidated derivatives of dihydrotestosterone metabolites (androstane-3 alpha, 17 beta-diol glucuronide, androstane-3 beta, 17 beta-diol glucuronide, and androsterone glucuronide) were reduced by 45-50%,suggesting that 5 alpha-reductase activity in peripheral tissues may show a compensatory increase during aging. Analysis of the fatty acid esters of DHEA (DHEA-FA) also revealed that these nonpolar steroids markedly decrease between 40-80 yr of age, although such a decrease in DHEA-FA levels was smaller than that in DHEA and DHEA-S, suggesting that the formation of DHEA-FA may be specifically increased during aging. In summary, the present study suggests that in contrast to the marked decline in activity of steroidogenic enzymes in the adrenals and the small decrease in the testis, the activity of the steroid-converting enzymes present in peripheral tissues does not decrease during aging. In fact, the marked decrease in DHEA formation by the adrenals leads to a decrease of about 50% in total androgens in men between the ages of 40-80 yr. Such a decrease probably affects many physiological processes during aging.



Ovarian suppression with triptorelin and adrenal stimulation with adrenocorticotropin in functional hyperadrogenism: role of adrenal and ovarian cytochrome P450c17 alpha.

Fertil Steril (UNITED STATES) Sep 1994, 62 (3) p521-30

OBJECTIVES: To validate combined ovarian suppression with triptorelin and adrenal stimulation with ACTH in the diagnosis of female hyperandrogenism and to provide new insights into the adrenal-ovarian relationship present in this disorder. DESIGN: Comparison of sexual steroids and basal and ACTH-stimulated steroid levels before and after ovarian suppression induced by triptorelin. SETTING: Department of Endocrinology, Hospital Ramon y Cajal, Madrid, Spain. PARTICIPANTS: Thirty-nine nonselected women with hyperandrogenism. MAIN OUTCOME MEASURES: Serum levels of T, 17-hydroxyprogesterone (17-OHP), 17-hydroxy-pregnenolone, DHEA and DHEAS, androstenedione (delta 4-A), 11-deoxycortisol, and cortisol. RESULTS: Elevated T independent of ovarian suppression pointed to an adrenal disorder in six patients (one with an androgen-producing adenoma, two with late-onset 21-hydroxylase deficiency, three with functional adrenal hyperandrogenism). Nineteen patients had functional ovarian hyperandrogenism as elevated T normalized after ovarian suppression and were subdivided into ovDHEAS+ (n = 7) and ovDHEAS = (n = 12)subgroups depending on the presence of DHEAS hypersecretion. Finally, 14 patients had idiopathic hirsutism according to normal T before and after ovarian suppression. Comparisons of initial hormonal values between groups and with reference values obtained from normal women (n = 11) disclosed in functional adrenal hyperandrogenism an elevation of T and basal and stimulated DHEAS, delta 4-A, and 17-OHP with respect to normal women. These abnormalities were also present in ovDHEAS+ except for basal delta 4-A,which was normal, whereas only T and stimulated 17-OHP were elevated in ovDHEAS =. In the idiopathic group all steroids were normal with the exception of a mild elevation in stimulated DHEAS. CONCLUSIONS: These results show a continuum of abnormalities in hyperandrogenic women, suggesting an enhanced cytochrome P450c17 alpha activity in the adrenal and the ovary as the shared mechanism between functional adrenal hyperandrogenism and functional ovarian hyperandrogenism.



Memory-enhancing effects in male mice of pregnenolone and steroids metabolically derived from it.

Proc Natl Acad Sci U S A (UNITED STATES) Mar 1 1992, 89 (5) p1567-71

Immediate post-training intracerebroventricular administration to male mice of pregnenolone (P), pregnenolone sulfate (PS), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), androstenedione, testosterone, dihydrotestosterone, or aldosterone caused improvement of retention for footshock active avoidance training, while estrone, estradiol, progesterone, or 16 beta-bromoepiandrosterone did not. Dose-response curves were obtained for P, PS, DHEA, and testosterone. P and PS were the most potent, PS showing significant effects at 3.5 fmol per mouse. The active steroids did not show discernible structural features or known membrane or biochemical effects that correlated with their memory-enhancing capacity. The above, together with the findings that DHEA acted even when given at 1 hr after training and that P, PS, and DHEA improved retention over a much wider dose range than do excitatory memory enhancers, led to the suggestion that the effects of the active steroids converge at the facilitation of transcription of immediate-early genes. P and PS, for which receptors have not yet been demonstrated, may exert their effects by serving as precursors for the formation of a panoply of different steroids, ensuring near-optimal modulation of transcription of immediate-early genes required for achieving the plastic changes of memory processes. Low serum levels of P in aging and the increases of cancer and behavioral disorders in individuals receiving drugs that block synthesis of cholesterol, the immediate precursor of P, suggest possible clinical utility for P.

image