Showing papers on "Pregnenolone published in 1983"
TL;DR: It is concluded that ketoconazole may be a general inhibitor of mitochondrial P450 enzymes, and the possibility that this drug action may be beneficially exploited in situations where inhibition of steroidogenesis is a therapeutic goal is raised.
Abstract: Ketoconazole has recently been shown to interfere with steroidogenesis in patients and rat in vitro systems. In this study we attempted to elucidate the site of inhibition in the adrenal gland. Although ketoconazole impaired adrenocorticotropic hormone stimulated cyclic (c)AMP production, dibutyrl cAMP addition did not bypass the steroidogenic blockade indicating that the critical ketoconazole-inhibited step was distal to cAMP. Addition of radiolabeled substrates to isolated adrenal cells and analysis of products by high performance liquid chromatography demonstrated a ketoconazole block between deoxycorticosterone (DOC) and corticosterone. This 11-hydroxylase step is carried out by a P450-dependent mitochondrial enzyme. No restriction of progesterone or pregnenolone conversion to DOC was detected, steps carried out by non-P450-dependent microsomal enzymes. Inhibition of cholesterol conversion to pregnenolone by mitochondrial fractions indicated a second block at the side chain cleavage step, another mitochondrial P450-dependent enzyme. Adrenal malate dehydrogenase, a non-P450-dependent mitochondrial enzyme was not inhibited while renal 24-hydroxylase, a P450-dependent mitochondrial enzyme in another organ, was blocked by ketoconazole. We conclude that ketoconazole may be a general inhibitor of mitochondrial P450 enzymes. This finding suggests that patients receiving ketoconazole be monitored for side effects relevant to P450 enzyme inhibition. Further, we raise the possibility that this drug action may be beneficially exploited in situations where inhibition of steroidogenesis is a therapeutic goal.
413 citations
TL;DR: Brain P and PS levels did not seem to depend on steroidogenic gland secretion: no meaningful difference occurred in brain 15 days after adrenalectomy plus orchiectomy, compared with sham-operated controls and it is proposed that P andPS formation or accumulation in the rat brain depend on in situ mechanisms unrelated to the peripheral endocrine gland system.
365 citations
TL;DR: The results imply that SCP2 enhances mitochondrial pregnenolone production by improving transfer of mitochondrial cholesterol to cytochrome P-450scc on the inner membrane, but does not directly influence the interaction of substrate with the hemoprotein.
137 citations
TL;DR: The peptide exhibits properties that are believed to characterize the hypothetical corticotropin-dependent labile activator of adrenal steroidogenesis.
Abstract: A cytosolic peptide activator (Mr approximately equal to 2,200) of cholesterol side-chain cleavage in the adrenal cortex has been isolated from normal corticotropin-treated rats and from rats implanted with the MtT/F4 corticotropin-secreting pituitary tumor. The isolation techniques were those common to peptide hormone purification, including tissue extraction into a highly acidic medium, gel filtration, and reverse-phase HPLC. The amino acid composition has been determined on acid hydrolysates. The activity of this adrenal peptide is acutely increased in hypophysectomized animals treated with corticotropin, and this increase is blocked by cycloheximide. The addition of activator peptide to adrenal mitochondrial preparations results in a rapid stimulation of pregnenolone formation that is dependent on activator concentration and a source of NADPH. In the absence of NADPH, addition of activator peptide to adrenal mitochondria increases the rate of cholesterol association with side-chain cleavage cytochrome P-450. The peptide therefore exhibits properties that are believed to characterize the hypothetical corticotropin-dependent labile activator of adrenal steroidogenesis.
131 citations
TL;DR: Investigations indicate that insulin acts on ovarian cells selectively to stimulate pregnenolone (but not estrogen) biosynthesis, and that specific trophic actions of insulin or insulinlike growth factors are likely to significantly regulate the differentiated function of the Graafian follicle in vivo.
Abstract: Direct actions of insulin on gonadal tissues have been difficult to demonstrate in vivo. We have developed an in vitro system in which swine ovarian cells remain highly responsive to trophic actions of insulin. Purified porcine insulin significantly augmented the biosynthesis and secretion of progesterone by cultured granulosa cells. These stimulatory actions of insulin were dose- and time-dependent and saturable. Under serum-restricted conditions, insulin also significantly amplified the capacity of estradiol and 8-bromo cyclic AMP to stimulate progesterone production. Inhibitors of protein and RNA synthesis (cycloheximide, actinomycin D, and alpha-amanatin) inhibited insulin action. The stimulation of progesterone production by insulin was attributable to increased biosynthesis of pregnenolone, rather than diminished catabolism of progesterone to its principal metabolite, 20α-hydroxypregn-4-en-3-one. Insulin also enhanced progesterone production in the presence of a soluble sterol substrate, 5-cholesten-3β,25-diol, which readily gains access to the mitochondrial cholesterol side-chain cleavage system. Moreover, exposure of granulosa cells to insulin produced a three- to sevenfold increase in mitochondrial content of cytochrome P-450 measured by difference spectroscopy, with a corresponding increase in mitochondrial cholesterol side-chain cleavage activity.
The capacity of insulin to facilitate progesterone biosynthesis by ovarian cells was mimicked by the insulinlike somatomedin, multiplication stimulating activity, but not by epidermal growth factor, fibroblast growth factor, or porcine relaxin. Insulin's augmentation of progesterone production reflected a selective action on progestin biosynthesis, since insulin significantly suppressed estrogen biosynthesis by granulosa cells.
Thus, our investigations indicate that insulin acts on ovarian cells selectively to stimulate pregnenolone (but not estrogen) biosynthesis. The actions of insulin are exerted by processes that require protein and RNA synthesis, and by mechanisms that augment mitochondrial cytochrome P-450 content and facilitate the utilization of cholesterol in the side-chain cleavage reaction. The striking mimicry of insulin effect by multiplication stimulating activity suggests that insulin action may be mediated through somatomedin receptors. Moreover, in view of the high concentrations of somatomedin in ovarian follicles in vivo, our in vitro observations suggest that specific trophic actions of insulin or insulinlike growth factors are likely to significantly regulate the differentiated function of the Graafian follicle in vivo.
97 citations
TL;DR: It appears that the decline in Leydig cell function in aged men is attributable to a reduced supply of mitochondrial steroid precursors rather than to an impairment in microsomal steroidogenesis.
Abstract: To determine the basis for the decline in testosterone production by the aged testis, intratesticular unconjugated steroids, including testosterone, pregnenolone (3β-hydroxy-5-pregnen-20-one), 17α-hydroxypregnenolone (3β,17α-dihydroxy-5-pregnen-20-one), dehydroepiandrosterone (3β-hydroxy-5-androsten-17-one), androstenediol (5-androstene-3β,17β-diol), progesterone, 17α-hydroxyprogesterone, androstenedione (4-androstene-3,17-dione), and 17β-estradiol, were measured by simultaneous RIAs in 32 previously untreated elderly men (aged 61–85 yr) undergoing orchiectomy as therapy for prostatic carcinoma and 20 young men (aged 25–35 yr) with oligospermia and varicocele. In vitro steroidogenesis using labeled pregnenolone as substrate was also investigated.Serum and intratesticular testosterone levels were lower (P < 0.05) in aged patients [3.3 ± 1.9 ng/ml and 0.86 ± 0.53 μg/g tissue (mean ± SD)] than in young men (6.4 ± 1.9 ng/ml and 1.7 ±1.1 μg/g tissue), while circulating LH levels were higher (P < 0.05) in elder...
67 citations
TL;DR: Modulation of the progestin biosynthetic pathway by the luteotropic agents, as well as the actions of GnRH, appears to result from a preferential increase in 20 alpha-HSD activity, while the GnRH inhibition of hCG-stimulated progesterone production appears to be a preferential inhibition of pregnenolone production.
Abstract: Prolactin (Prl), beta 2-adrenergic agents and human chorionic gonadotropin (hCG) are luteotropic in rats, whereas gonadotropin releasing hormone (GnRH) exerts direct inhibitory effects on ovarian steroidogenesis. The present study examined the modulation of the progestin biosynthetic pathway by the luteotropic agents, as well as the actions of GnRH. Rat granulosa cells were primed with follicle-stimulating hormone (FSH) to increase their responsiveness to the luteotropic agents. Subsequent treatment for 2 days with Prl, terbutaline (a beta 2-adrenergic agonist) or hCG stimulated the production of progesterone, 20 alpha-hydroxypregn-4-en-3-one (20 alpha-OH-P), pregnenolone and the activity of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD). In contrast, treatment with Prl or terbutaline, but not hCG, inhibited 20 alpha-hydroxysteroid dehydrogenase (20 alpha-HSD) activity by decreasing the apparent maximal velocity of the enzyme with no change in its Km value. Concomitant treatment with GnRH inhibited progesterone, but increased 20 alpha-OH-P production stimulated by Prl or terbutaline. These effects were associated with a stimulation of 20 alpha-HSD activity, while neither 3 beta-HSD activity nor pregnenolone biosynthesis was decreased. In contrast, GnRH inhibited progesterone production in hCG-treated cells without affecting 20 alpha-OH-P production. This was associated with an inhibitory effect of GnRH on pregnenolone biosynthesis with no effect upon 3 beta-HSD activity. Thus, Prl and the beta 2-agonist stimulate progesterone production in granulosa cells by increasing pregnenolone production and 3 beta-HSD activity as well as by decreasing 20 alpha-HSD activity, while hCG stimulates progesterone production by increasing pregnenolone production and 3 beta-HSD activity. The inhibitory effect of GnRH on Prl- or terbutaline-stimulated progesterone production appears to result from a preferential increase in 20 alpha-HSD activity, while the GnRH inhibition of hCG-stimulated progesterone production appears to result from a preferential inhibition of pregnenolone production.
52 citations
TL;DR: Proteins which are immunochemically compatible with hepatic SCP2 appear to be present in steroidogenic tissues and may play a role in control of mitochondrial cholesterol side chain cleavage activity.
51 citations
TL;DR: The hypothesis of a steroid-induced functional zonation of the adrenal cortex is supported by ACTH-mediated induction of bovine zone glomerulosa 17-hydroxylase activity and suppression of glomeruosa aldosterone production, which results in effective conversion of functional glomersulosa cells to functional fasciculata cells.
50 citations
TL;DR: In vitro findings suggest that progestins may exert an autoregulatory positive feedback action to enhance gonadotropin-stimulated production of progesterone and 20α-OH-P.
Abstract: Ovarian progesterone production is stimulated by FSH and LH. Concomitant treatment with a synthetic progestin, R5020, (10-6 M) increases the FSH-stimulated production of progesterone and 20α-hydroxypregn-4-en-3-one (20α-OH-P) in cultured rat granulosa cells. Likewise, R5020 augments the LH-stimulated progestin production in FSH-primed cells. Furthermore, the FSH stimulation of pregnenolone biosynthesis is enhanced by 10-6 M of progesterone or R5020. These in vitro findings suggest that progestins may exert an autoregulatory positive feedback action to enhance gonadotropin-stimulated production of progesterone and 20α-OH-P.
47 citations
TL;DR: The results show that the ovaries of both species produce steroids that are active in the induction of oocyte final maturation and are effective in inducing GVBD in the bioassays.
TL;DR: The present studies indicate that human granulosa-luteal cells isolated from preovulatory follicles induced with exogenous gonadotropins and hCG secrete large quantities of progesterone in vitro.
Abstract: Human granulosa-luteal cells were harvested from preovulatory Graafian follicles at the time of oocyte retrieval for in vitro fertilization after induction of follicle maturation by sequential injections of menopausal gonadotropins and hCG. Such highly differentiated granulosa cells produced large quantities of progesterone basally (6.8 pg/cell X 2 days) in monolayer culture. Human LH significantly increased progesterone biosynthesis after 6, 12, 48, 96, or 144 h in culture, with a maximal increase of 8- to 20-fold occurring at 96 h. The stimulatory effect of LH could be observed under serum-free conditions and was maximal in the presence of 4% serum. Human granulosa-luteal cells also exhibited significant stimulatory responses to hCG, prostaglandin E2, or the cAMP effectors 8-bromo cAMP, choleratoxin, or forskolin in serum-free incubations. Concentrations of 17 beta-estradiol that are attained physiologically in ovarian follicles in vivo markedly suppressed basal and LH (or cAMP)-stimulated progesterone production in vitro (maximal suppression, greater than 90%). The nonaromatizable androgen 5 alpha-dihydrotestosterone also inhibited progesterone production, but by no more than 45-50% even at supraphysiological concentrations. Estradiol's blockade of progesterone synthesis was associated with a corresponding increase in pregnenolone accumulation. The present studies indicate that human granulosa-luteal cells isolated from preovulatory follicles induced with exogenous gonadotropins and hCG secrete large quantities of progesterone in vitro. Such cells retain stimulatory responses to human LH, hCG, prostaglandin E2, and classical cAMP effectors in serum-free incubations. Moreover, physiological concentrations of 17 beta-estradiol suppress progesterone production, probably by inhibiting cellular conversion of pregnenolone to progesterone. Thus, the present in vitro system permits an investigation of hormone action in well differentiated, human granulosa-luteal cells isolated from preovulatory Graafian follicles that have a defined endocrine history of prior gonadotropin exposure in vivo.
TL;DR: The following acetylenic steroids appear to be the first reported mechanism-based inhibitors of cytochrome P-450scc: 20-(1,5-hexadiynyl)-5-pregnen-3 beta, 20 alpha-diol under turnover conditions completely inactivates the enzyme with a half-time of 11 min.
TL;DR: Electron microscopic examination of sections prepared from fresh adrenal tissue fixed in glutaraldehyde, revealed that the enzyme was predominantly clustered around lipid droplets, and it is suggested that this may reflect an association of organelles, cholesterol being transported from lipid Droplets to surrounding mitochondria, and pregnenolone then being converted to dehydroepiandrosterone in the adjacent endoplasmic reticulum and thence immediately sulfurylated.
Abstract: Dehydroepiandrosterone sulfate is the major secretory product of the human adrenal cortex. The enzyme responsible for the sulfurylation, which has been isolated previously, possesses kinetic properties suggesting that it plays an important regulatory role in dehydroepiandrosterone sulfate secretion. In order to study the localization of the enzyme in the respective zones and cells of the cortex, an antibody to the pure enzyme was raised and the immunoglobulin G fraction employed in the peroxidase-antiperoxidase method. Staining was confined to the zona reticularis but was unevenly distributed throughout the cells. Electron microscopic examination of sections prepared from fresh adrenal tissue fixed in glutaraldehyde, revealed that the enzyme was predominantly clustered around lipid droplets. It is suggested that this may reflect an association of organelles, cholesterol being transported from lipid droplets to surrounding mitochondria, and pregnenolone then being converted to dehydroepiandrosterone in the...
TL;DR: The effects of equivalent doses of two inhibitors of the 3‐beta‐hydroxy steroid dehydrogenase enzyme system—WIN 24540 (trilostane) and WIN 32729—on the secretion of progesterone in early human pregnancy are described.
Abstract: The effects of equivalent doses of 2 inhibitors of the 3-beta-hdyroxy steroid dehydrogenase enzyme system--WIN 24540 (trilostane) and WIN 32729--on the secretion of progesterone in early human pregnancy are described. Patients and controls less than 12 weeks pregnant were given a single dose of either drug and the resultant hormonal changes monitored for 7 1/2 hours. A consistent fall in plasma progesterone concentrations occurred at all dose levels and at the highest dose they fell to less than 50% of pretreatment levels. However while with trilostane the associated increase in plasma concentrations of pregnenolone was always accompanied by a rise in plasma DHA concentrations with WIN 32729 there appeared to be adrenal effect at the lower dosage levels. These data demonstrate inhibition of progesterone secretion in human pregnancy using nonhormonally active steroids. The pattern of steroid precursors indicates that while both drugs inhibit 3-beta-hydroxy steroid dehyrogenase activity WIN 32729 is more selective and only interferes with adrenal steroid biosynthesis at high doses. (authors)
TL;DR: Binding studies showed that the insignificant decrease in ACTH receptors could not account for the large changes in the responsiveness induced by prior exposure of cells to ACTH, which appears to result from a defect in the rate-limiting first step of the steroidogenic pathway, namely conversion of cholesterol to pregnenolone.
Abstract: The effects of prior exposure of normal rat adrenocortical cells to ACTH on the responsiveness of the cells to subsequent stimulation with the hormone have been studied. ACTH induces a time- and concentration-dependent refractoriness of both cAMP formation and steroidogenesis. Desensitization of either response was observed only upon activation of the response. Thus, both ACTH and 8-Br-cAMP caused desensitization of the steroidogenic response. The ACTH-induced desensitization of steroidogenesis, however, was completely prevented by blocking the steroidogenic action of ACTH with aminoglutethimide during exposure of cells to the hormone. Aminoglutethimide had no effect on ACTH-induced desensitization of the cAMP response. Studies with analogs of the hormone also confirmed that induction of desensitization of the steroidogenic response is independent of the desensitization of the cAMP response. Binding studies showed that the insignificant decrease in ACTH receptors could not account for the large changes in the responsiveness induced by prior exposure of cells to ACTH. Desensitization of the steroidogenic response appears to result from a defect in the rate-limiting first step of the steroidogenic pathway, namely conversion of cholesterol to pregnenolone.
TL;DR: The production of progesterone (P) and estrogen (E) by enzymatically dispersed granulosa and theca cells from chicken preovulatory follicles was examined and the contribution of each cell type in the production of steroids by chicken follicles during maturation was discussed.
Abstract: The production of progesterone (P) and estrogen (E) by enzymatically dispersed granulosa and theca cells from chicken preovulatory follicles was examined in 3-h incubations. Accumulation of the P produced by granulosa cells was significantly reduced by the addition of theca cells, whereas E production was increased. The decrease in P accumulation was shown to be due to extensive metabolism of P by theca cells. There were no synergistic effects of luteinizing hormone (LH) and any substrate tested on E production by theca cells. Maturation of granulosa cells was characterized by an increased sensitivity to LH stimulation of P production, but there was no change in pregnenolone conversion to P. Conversely, maturation of theca cells was accompanied by decreased in both sensitivity to LH and the ability to convert substrates to E. The results are discussed in terms of the contribution of each cell type in the production of steroids by chicken follicles during maturation.
TL;DR: The results show that the de novo synthesis of cholesterol is able to account for only 25% of the maximal steroidogenic capacity of pig Leydig cells and that hCG-induced steroidogenic desensitization is only partially due to cholesterol depletion.
Abstract: Dispersed Leydig cells were prepared from pig testes and purified in a discontinuous Percoll gradient. About 95% of these cells stained for 3 beta-hydroxysteroid dehydrogenase. The cells were cultured in a chemically defined medium. Testosterone production was low (2 +/- 0.4 ng/10(6) cells/day) under basal conditions, but increased by 8- to 10-fold on the third day of daily human CG (hCG) treatment. Addition to the medium of both human and pig low density lipoprotein (LDL) produced a dramatic increase in both basal (8-fold) and acute hCG-stimulated (5-fold) testosterone production, whereas both human and pig high density lipoprotein were far less effective. Furthermore the effect of lipoproteins was synergistic with that of hCG. The effects of human LDL on both basal and hCG-stimulated testosterone productions were dose-dependent. Maximum effect was achieved at a protein concentration of 10-40 micrograms/ml with an ED50 of about 4 micrograms/ml. Three days of pretreatment with hCG or (Bu)2cAMP alone induced Leydig cell steroidogenic refractoriness to both hCG and (Bu)2cAMP stimulation. Concomitant treatment with LDL restored the steroidogenic capacity, but only partially. Production of pregnenolone and testosterone of desensitized cells was significantly higher than that of control cells under basal conditions, but was 60% and 40% lower, respectively, after acute hCG stimulation. Moreover, the conversion of exogenous pregnenolone to testosterone by desensitized cells was only 60% of that of control cells. These results show that the de novo synthesis of cholesterol is able to account for only 25% of the maximal steroidogenic capacity of pig Leydig cells and that hCG-induced steroidogenic desensitization is only partially due to cholesterol depletion.
TL;DR: The results of this study demonstrate for the first time the presence of two components of the cholesterol side chain cleavage system in freshly obtained granulosa cells, and provide direct evidence for the trophic effect of FSH and its presumed mediator, cyclic AMP, on the synthesis of cytochrome P-450scc in granULosa cells.
TL;DR: Cholesterol synthesized de novo was the likely steroidogenic precursor in the acute hormonally stimulated fetal adrenal cells and confirmed that 3 beta-hydroxysteroid formation is the principal steroidogenic fate of cholesterol in these cells.
Abstract: Steroidogenesis in dispersed fetal zone cells of midtrimester human fetal adrenal was stimulated acutely by ACTH. Polypeptide hormones such as hCG, αMSH, ovine PRL, and LH did not produce a similar stimulation of steroidogenesis. The principal steroid products of ACTH-stimulated fetal adrenal cells were dehydroisoandrosterone sulfate, pregnenolone, pregnenolone sulfate, and 17α-hydroxypregnenolone. Only minimal production of the δ4-3-ketosteroids, cortisol, corticosterone, and progesterone, was observed. Cyanoketone (2α-cyano-4,4,17α-trimethyl-17β-hydroxyandrost-5-en-3-one; an inhibitor of 3β-hydroxysteroid dehydrogenase activity) treatment of the cells caused only a minor increase in 3β-hydroxysteroid formation, confirming that 3β-hydroxysteroid formation is the principal steroidogenic fate of cholesterol in these cells. SU-10603 [7-chloro-3,4-dihydro-2-(3-pyridyl)naphthalen-1-(2H)one; a steroid 17α-hydroxylase inhibitor] treatment of the cells caused a marked accumulation of pregnenolone sulfate, indica...
TL;DR: Mixtures of zona fasciculata and zona reticularis cells, obtained by enzyme dispersion of decapsulated guinea-pig adrenal glands, were separated by unit gravity sedimentation or by equilibrium density sedimentation and it was found that (1-24)ACTH stimulated greater steroid production by the ZF cells compared with the ZR cells.
Abstract: Mixtures of zona fasciculata (ZF) and zona reticularis (ZR) cells, obtained by enzyme dispersion of decapsulated guinea-pig adrenal glands, were separated either by unit gravity sedimentation or by equilibrium density sedimentation. There was no evidence of deleterious effects on ultrastructural integrity or the ability of cells to respond to (1-24)ACTH (Synacthen) after either separation technique. Unit gravity sedimentation gave one fraction in which 90% of the cells were from the ZR and another fraction in which 70% of the cells were from the ZF. Equilibrium density sedimentation of cell mixtures on Percoll gradients gave fractions containing either 90% pure ZR or 95% pure ZF cells. Cortisol, 11-deoxycortisol, corticosterone, deoxycorticosterone, 11 beta-hydroxyandrostenedione and androstenedione were all formed from [14C]pregnenolone on incubation with purified preparations of both types of cell. No product was seen to be unique to either cell type although ZR cells appeared deficient in 11 beta-hydroxylase activity relative to ZF cells. The ratio of androstenedione to cortisol (formed either from labelled pregnenolone or from endogenous precursors) was higher for ZR cells than for ZF cells. When the purer cells obtained by equilibrium density sedimentation were studied, it was found that (1-24)ACTH stimulated greater steroid production (both androstenedione and cortisol) by the ZF cells compared with the ZR cells.
TL;DR: Both C-ACTH and P-AC TH for 72 h increase fetal adrenal responses, but the pattern of corticosteroid output in vitro is determined by the mode of ACTH administration in vivo, and adrenal responsiveness is increased further between 72 and 100 h of P- ACTH.
Abstract: We have examined 1) the effects of mode of ACTH administration to fetal sheep in vivo on the pattern of corticosteroid output by dispersed adrenal cells in vitro, and 2) the time course of fetal adrenal activation during pulsatile ACTH administration to the fetus Fetal sheep received the same amount of ACTH either as a continuous infusion (C-ACTH; 05 μg/h) or as 15-min pulses every 2 h for 72 h (P-ACTH) Other fetuses received P-ACTH until labor occurred (mean, 100 h) or saline for 72 or 100 h Adrenal cells from fetuses that received C-ACTH for 72 h produced more corticosterone from endogenous precursors after the addition of ACTH in vitro and after the addition of 03 μM progesterone (P4) or pregnenolone (P5) than cells from fetuses treated with P-ACTH for 72 h There was no difference in cortisol (F) response between the two groups, although in both groups F output was greater than in controls Adrenal cells from control fetuses produced more P4 in vitro during incubation with ACTH plus guanosine-5′-
TL;DR: Results are indicative that ACTH acts in diverse manners on the bovine adrenocortical cell to affect corticosteroid secretion, and the long term effect of ACTH was to enhance the relative secretion of 17 alpha-hydroxylated steroids and C19-steroids.
TL;DR: The responses of peripheral serum steroids to a single injection of hCG were compared in adult male rats and humans to show the magnitude of the rapid steroidogenic response to hCG, which is very small in man and indicates smaller supply or lesser metabolism of mitochondrial cholesterol in human testis.
TL;DR: The results suggest that granulosa cells contribute to thecal androgen production by providing steroid substrate, which would provide a means for granul Rosa cells to control the availability of aromatizable androgens.
Abstract: The role of granulosa cells on porcine follicular androgen synthesis was studied. Granulosa cells were cultured for 24 h either in Eagle's minimum essential medium (MEM) or in MEM plus follicle-stimulating hormone (FSH; 1 microgram/mL). Thecal preparations were cultured with or without luteinizing hormone (LH), either in MEM, 50% "spent media" from granulosa cells control (MA) or 50% "spent media" from granulosa cells incubated with FSH (MB). In the absence of LH, MB stimulated accumulation of both delta 4-androstenedione (twofold) and testosterone (threefold). MB was found to contain high levels of C21-steroids, including progesterone and material which behaves chromatographically and immunologically like pregnenolone. These amounts of C21-steroids were able to stimulate thecal androgen production. The results suggest that granulosa cells contribute to thecal androgen production by providing steroid substrate. This would provide a means for granulosa cells to control the availability of aromatizable androgens.
TL;DR: It is proposed that during the NMS the predominant route of testosterone biosynthesis is pregnenolone leads to 17 alpha-hydroxypregnenol one leads to dehydroepiandrosterone, which leads to androst-5-en-3 beta, 17 beta-diol leads to testosterone.
TL;DR: It is concluded that this system is a useful model for studying progesterone production by human placental tissue, and that placental progestersone production may be significantly influenced by the presence of other steroid hormones.
01 Jul 1983
TL;DR: The data support a coordinate action of ACTH and pro-gamma-melanotropin in controlling cholesterol metabolism in the adrenal cortex following stress and the provision of free cholesterol for the cytochrome P-450scc enzyme system may also be controlled.
Abstract: Adrenal and serum corticosterone concentrations, cholesterol association with adrenal cortical cytochrome P-450scc (the cytochrome P-450 catalyzing the conversion of cholesterol to pregnenolone), and adrenal cortical activities of cholesteryl ester hydrolase, acyl-CoA:cholesterol acyltransferase, and cholesterol side-chain cleavage have been determined at various times following stress in female rats. The paramount importance of cholesterol side-chain cleavage activation in the response to stress at the low point of the circadian rhythm is confirmed. At the high point of the circadian rhythm, there is evidence that the provision of free cholesterol for the cytochrome P-450scc enzyme system may also be controlled. The data support a coordinate action of ACTH and pro-gamma-melanotropin in controlling cholesterol metabolism in the adrenal cortex following stress.
TL;DR: THC exerts direct inhibitory effects on FSH-dependent functions related to steroidogenesis and the acquisition of LH receptors, all of which are essential to follicular maturation.
Abstract: The direct effects of delta 9-tetrahydrocannabinol (THC) and related cannabinoids on ovarian granulosa cells were studied in vitro. Granulosa cells from immature, hypophysectomized, estrogen-treated rats were cultured for 2 days in an androstenedione-supplemented medium in the presence or absence of follicle-stimulating hormone (FSH) (10 ng/ml) with or without cannabinoids. FSH treatment increased progesterone and estrogen biosynthesis, whereas concomitant treatment with THC led to a dose-dependent inhibition of the FSH-stimulated accumulation of progesterone and estrogen with ED50 values of 3.5 +/- 0.3 X 10(-7) and 1.8 +/- 0.2 X 10(-6) M, respectively. Treatment with related but nonpsychoactive cannabinoids (cannabidiol, cannabinol, cannabigerol, or cannabichromene) was equally effective. The THC-induced inhibition of progesterone production was reversible and was associated with an inhibition of pregnenolone biosynthesis and a decrease of 3 beta-hydroxysteroid dehydrogenase activity. In addition, treatment with THC brought about a dose-dependent inhibition of the FSH-induced increase in luteinizing hormone (LH) receptors. The inhibitory effects of THC were not associated with changes in cell number, protein content, or cell viability. Thus, THC exerts direct inhibitory effects on FSH-dependent functions related to steroidogenesis and the acquisition of LH receptors, all of which are essential to follicular maturation. Because plasma concentrations of THC similar to those used in this study have been reported in human beings, repeated exposure of female users to THC may lead to ovarian dysfunction, due in part, to the direct antigonadal activity to THC.
TL;DR: In this paper, the results suggest that steroidogenesis, through the adenylate cyclase-cyclic adenosine 3':5'-monophosphate system, in human oocytes may play some important role in oocyte maturation, fertilization, and early embryonic development.