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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasma testosterone (T), dihydrotestosterone (DHT), 17-hydroxyprogesterone (17OHP), androstenedione (A), estradiol (E2), and dehydroepiandrosterone sulfate (DHAS) were measured by radioimmunoassay after celite chromatography prior to and after a 3-hour infusion of the synthetic gonadotropin releasing factor, GnRH, in normal prepubertal and pubertal boys. Plasma T levels rose (p less than 0.001) in the pubertal but not prepubertal boys. 17OHP concentrations increased in those boys who had an increment of T. A, DHT, E2 or DHAS levels did not increase after GnRH. Basal levels of T, DHT, A and DHAS correlated with the peak and mean serum LH levels attained during the GnRH infusion. These data confirm the greater Leydig cell responsivity to transient rises of endogenous gonadotropin in pubertal males and also suggest that there may be a relationship between adrenal androgen production and maturation of the hypothalamic-pituitary-gonadal system.
Steroids 1976 Dec
PMID:Effect of infusion of gonadotropin releasing hormone upon plasma concentrations of sex hormones in prepubertal and pubertal males. 13 15

Hypophysectomy of immature rats results after 5 days in a loss of LH responsiveness of Leydig cells. LH responsiveness can be partly maintained by treatment with FSH for 5 days. When estradiol benzoate was administered together with FSH to hypophysectomized rats the maintenance of LH responsiveness was not observed. The loss in LH responsiveness after hypophysectomy in terms of testosterone production could not be explained by either a change in the amount of Leydig cells present in the Leydig cell preparation or to a higher conversion of testosterone. The LH-stimulated cAMP production in cells from hypophysectomized rats was very low compared to cells from intact rats. There was no difference between cAMP production of Leydig cells from untreated, FSH-treated or FSH plus estradiol benzoate treated hypophysectomized rats. During the first 2 days after hypophysectomy LH responsiveness in both untreated and FSH-treated rats showed a comparable decrease. From day 2 after hypophysectomy LH responsiveness remained at a constant level in cells from rats treated with FSH, but declined further in cells from untreated rats. A single injection of estradiol benzoate to hypophysectomized rats treated with FSH counteracted the effect of FSH on LH responsiveness, but only when estradiol was administered at that time after hypophysectomy, when the effect of FSH on LH responsiveness was clear.
Steroids 1978 Jan
PMID:Further characterization of the effects of hypophysectomy, FSH and estrogen on LH stimulation of testosterone production in Leydig cells isolated from immature rats. 20 98

This study was conducted to examine interstitial cell proliferation in the testis of the ethylene dimethane sulfonate (EDS)-treated rat. Initial autoradiographic studies demonstrated a peak of [3H]thymidine incorporation by interstitial cells at 2 and 4 days post-EDS treatment. Subsequent studies were designed using in vivo pulse labeling regimens in an attempt to identify interstitial cell proliferation associated with Leydig cell regeneration. Rats were injected with [3H]thymidine at days 2 and 4 post-EDS and were killed 6 hours later or at 30 days post-EDS. Although cells labeled at 2 and 4 days post-EDS appeared to undergo subsequent division, the Leydig cells visible at 30 days post-EDS were not labeled. In a second study, rats were injected with [3H]thymidine at days 10 and 20 post-EDS and were killed either 6 hours later or at 24 days post-EDS. In the 10-day post-EDS group, interstitial cells were labeled at both the 6-hour and 24-day time points; however, Leydig cells present at 24 days were not labeled. In contrast, the testes of rats that were killed at 20 days post-EDS (6 hours labeling period) contained Leydig cells that displayed grains over the nucleus, thus suggesting that Leydig cell proliferation had occurred. In addition, a high number of the Leydig cells observed at 24 days post-EDS were labeled, suggesting that they arose from divisions occurring during the 20- to 24-day post-EDS period. These studies demonstrate that interstitial cell proliferation occurs in several stages following EDS treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Steroids 1991 Feb
PMID:Interstitial cell proliferation in the testis of the ethylene dimethane sulfonate-treated rat. 185 May 65

Hyperinsulinism is associated with disorders of androgen production in humans. We have studied the effects of insulin and insulin-like growth factor-1 on androgen production in vitro using a crude preparation of mouse Leydig cells incubated with luteinizing hormone in a serum-free medium. We found a positive correlation between testosterone production and the luteinizing hormone dose over 3 hours. Exposure of the cells for 1 hour to insulin (1 micrograms/ml) prior to the addition of luteinizing hormone significantly augmented the amount of testosterone produced in response to the gonadotropin when added after this preincubation. In contrast, prior exposure of the cells to proinsulin (30 micrograms/ml), insulin-like growth factor-1 (30 ng/ml), or epidermal growth factor-1 (1 micrograms/ml) did not influence the testosterone response to luteinizing hormone. Transforming growth factor-beta reduced the testosterone response to luteinizing hormone. Transforming growth factor-beta (1,000 pg/ml) blocked the insulin augmentation of luteinizing hormone-stimulated testosterone production. We conclude that insulin has an endocrine effect on testosterone production by mouse Leydig cells in vitro. Furthermore, the Leydig cell response to insulin is itself sensitive to interaction with transforming growth factor-beta which may operate as part of the paracrine control of Leydig cell function.
Steroids 1990 Jun
PMID:Regulation of testicular function by insulin and transforming growth factor-beta. 220 Nov 4

Primary cultures of interstitial cells were prepared from the testis of mice, rats, and pigs. The cells were grown in a defined medium supplemented with low (0.1%) serum and insulin, transferrin and epidermal growth factor. Comparisons of the interstitial cell cultures from the three species were made for plating efficiency, cell survival, maintenance of hCG receptors and maintenance of steroidogenic responsiveness to hCG. The porcine cultures had a higher plating efficiency and higher hCG receptor levels per cell than Leydig cells from either rodent. Additionally, the porcine cells showed an increase in testosterone (T) production with hCG stimulation throughout their lifespan in culture while the rodent cultures showed a decrease in T stimulation with time with no stimulation by day 6 in culture. These data indicate that species differences exist in hCG receptor concentrations per cell, the maintenance of hCG receptors and steroidogenic response in culture. The initial high survival, purity and continued functional response of porcine interstitial cell cultures make them a superior system for the study of gonadotropin regulation of Leydig cell function.
Steroids 1981 Jul
PMID:Primary cultures of Leydig cells from rat, mouse and pig: advantages of porcine cells for the study of gonadotropin regulation of Leydig cell function. 627 Aug 52

We determined the concentration of steroids in blood plasma of CBF1 male mice and the steroidogenic potential of the mouse testis. Steroid secretion rates are based on measuring selected C18, C19, and C21 steroids in the venous effluent of testes perfused with a defined medium containing luteinizing hormone. Steroids were isolated by thin-layer and/or column chromatography and quantified by radioimmunoassay. These include pregnenolone, 17 alpha-hydroxypregnenolone, dehydroepiandrosterone, androstenediol, progesterone, 17 alpha-hydroxyprogesterone, androstenedione, testosterone, dihydrotestosterone, 3 alpha-androstanediol, and 3 beta-androstanediol. Testosterone is the primary steroid secreted by mouse testes perfused in vitro and is the chief androgen present in blood plasma. Pregnenolone, an obligatory intermediate in steroid synthesis, is converted to testosterone via two separate steroidogenic pathways in approximately equal proportions. This is unlike other species in which testosterone biosynthesis proceeds preferentially via either the delta 4 or the delta 5 pathway. Our results, taken together, provide the first comprehensive assessment of Leydig cell steroidogenic activity in the mouse, demonstrate putative enzymatic pathways subserving androgen biosynthesis, and establish the predominant steroids in the peripheral circulation of adult mice.
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PMID:Steroid secretion by mouse testes perfused in vitro. 685 49

Sertoli cells isolated from 17 day old rats were maintained in culture and incubated with [14C]-progesterone for 20 h. The cells and media were extracted with ether/chloroform and the extracts chromatographed two-dimensionally on TLC and the radioactive metabolites visualized by autoradiography. Nine of the metabolites (constituting about 88% of total metabolite radioactivity) were identified by relative mobilities of the compounds and their derivatives in TLC and GC systems and by recrystallizations with authentic steroids as the following: 20 alpha-hydroxypregn-4-en-3-one, 3 alpha-hydroxy-5 alpha-pregnan-20-one, 5 alpha-pregnane-3 alpha, 20 alpha-diol, 17 beta-hydroxy-5 alpha-androstan-3-one, 5 alpha-pregnane-3,20-dione, 17-hydroxypregn-4-ene-3,20-dione, testosterone, 5 alpha-androstane-3 alpha, 17 beta-diol and androst-4-ene-3,17-dione. Over 71% of the metabolite radioactivity was due to 20 alpha-hydroxypregn-4-en-3-one, the major metabolite. 5 alpha-reduced pregnanes constituted about 12% and C19 steroids comprised about 2.9% of the radioactivity of the metabolites. Calculation of relative steroidogenic enzyme activities from initial reaction rates suggested the following activities in muunits/mg Sertoli cell protein: 20 alpha-hydroxysteroid oxidoreductase (20 alpha-HSO; 7.71), 5 alpha-reductase (4.77), 3 alpha-HASO (3.57), 17 alpha-hydroxylase (0.93), 17 beta-HSO (0.34) and C17-C20 lyase (0.34). The relatively high rate of steroidogenic enzyme activities in the Sertoli cells of young rats may indicate that Sertoli cells are less dependent on Leydig cell steroidogenesis than has been assumed. Since nearly all the metabolites of progesterone and testosterone are now identified, it is possible to construct a picture of Sertoli cell steroidogenic activity.
Steroids 1980 May
PMID:An analysis of the metabolites of progesterone produced by isolated Sertoli cells at the onset of gametogenesis. 699 80

To characterize Leydig cell steroidogensis, we examined the metabolism of [3H]pregnenolone (3 beta-hydroxy-5-pregnen-20-one) to androgens in the presence and absence of human chorionic gonadotropin (hCG) as a function of culture duration. Approximately 20-30% of the (3H)pregnenolone was converted to testosterone (17 beta-hydroxy-4-androsten-3-one) by purified Leydig cells at 0, 3 and 5 days (d) of culture. Androstenedione (4-androstene-3,17-dione) and dihydrotestosterone (17 beta-hydroxy-5 alpha-androstan-3-one) were also produced while on day 5 of culture, significant amounts of progesterone (4-pregnene-3,20-dione) were isolated. The delta 5 intermediates, 17-hydroxypregnenolone (3 beta, 17-dihydroxy-5-pregnen-20-one) and dehydroepiandrosterone (3 beta-hydroxy-5-androsten-17-one), accounted for less than 1% of substrate conversion, indicating a clear preference for Leydig cells to metabolize (3H)pregnenolone via the delta 4 pathway. On day 0 of culture, unidentified metabolites considered of predominately polar steroids while on day 5 of culture, the unidentified metabolites consisted of predominately nonpolar steroids. In the presence of hCG, (3H-pregnenolone metabolism did not differ from basal on day 0 or 3 of culture. HCG increased the conversion of pregnenolone to progesterone and 17-hydroxyprogesterone (17-hydroxy-4-pregnene-3,20-dione) on 5d. This suggests that Leydig cells cultured for 5d have decreased C17-20 desmolase activity or that hCG acutely stimulates 3 beta-hydroxysteroid dehydrogenase and delta 5-delta 5 isomerase activities.
Steroids 1982 Nov
PMID:Steroid metabolism by purified adult rat Leydig cells in primary culture. 718 85

To reinvestigate the effect of hCG on circulating and urinary dehydroepiandrosterone sulfate (DHEAS), a hCG stimulation test (5000 IU administered i.m. at 8.30 h on 3 consecutive days) was performed in 6 healthy males (aged 24 to 35 years). Blood specimens and 24-h urine samples were collected immediately before the first and directly after the last hCG administration. Contrary to previous findings in normal men, the present study revealed significant DHEAS responses after testicular stimulation with hCG: plasma DHEAS increased from 7.9 +/- 2.3 to 9.6 +/- 2.2 mumol/L (P < 0.05) and urinary DHEAS from 5.7 +/- 3.6 to 9.3 +/- 5.2 mumol/day (P < 0.05). There was also a marked rise (P < 0.05) in the urinary excretion of total 17-ketosteroid sulfates. Clear increases of unconjugated plasma dehydroepiandrosterone as well as of circulating and renally excreted androstenedione and testosterone definitely confirmed an adequate Leydig cell stimulation. Significant post-hCG changes were additionally observed for plasma and urinary 3 alpha-androstanediol glucuronide (149% and 79% increases, respectively) and for urinary cortisol (21% decrease). Significant correlations were found for the post-hCG percent increases of plasma androstenedione versus plasma DHEAS (r = 0.86) and for the percent increases of plasma testosterone versus urinary DHEAS (r = 0.98), indicating that the extent of gonadal androgen elevations in the circulation of normal men is a determinant of DHEAS increases in blood or urine. These findings provide an explanation for the frequently observed sex differences for DHEAS in adults.(ABSTRACT TRUNCATED AT 250 WORDS)
Steroids 1995 Feb
PMID:Re-examination of the effect of hCG on plasma levels and renal excretion of dehydroepiandrosterone sulfate in healthy males. 761 86

A study of a large cell calcifying Sertoli cell tumor of the testis associated with bilateral gynecomastia in an 8-year-old boy is presented. Macroscopically, the two testes showed multiple, large, and hard calcified nodules. Histology revealed clusters or cords of tumor cells with foci of calcifications as well as evidences, in the adjacent testicular parenchyma, of initiation of gonadal development, such as early signs of spermatogenesis and sparse Leydig cell differentiation. In vivo, serum hormone studies showed gonadotropin-independent gonadal activity. After orchidectomy two macroscopically distinct fractions of the removed testes, tumoral and extratumoral, were processed separately for cell isolation and culture. The secretion of testosterone, androstenedione, and 17-hydroxyprogesterone to the medium on day 6 of culture showed that steroidogenesis in cells of the extratumoral fraction was more active than in the tumoral fraction. On the other hand, tumoral fraction cells showed much higher aromatase activity than extratumoral cells. Furthermore, conditioned medium of tumoral fraction cells was able to stimulate testosterone secretion when it was added to subcultures of testicular cells isolated from a control subject. It is postulated that tumoral cells might have stimulated neighboring interstitial cells to differentiate into Leydig cells and to secrete androgens, which in turn might have been aromatized to estrogens by tumoral cells.
Steroids 1995 Feb
PMID:Testicular steroid biosynthesis in a boy with a large cell calcifying Sertoli cell tumor producing prepubertal gynecomastia. 761 89


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