Concentrations Of 5α-dihydrotestosterone Research Articles

Combined MD and QM/MM Investigations of Hydride Reduction of 5α-Dihydrotestosterone Catalyzed by Human 3α-Hydroxysteroid Dehydrogenase Type 3: Importance of Noncovalent Interactions.

3α-Hydroxysteroid dehydrogenase (3α-HSD) is an enzyme that is essential in the regulation of the concentration of 5α-dihydrotestosterone (5α-DHT) in the prostate. It catalyzes the hydride reduction of 5α-DHT to 3α-androstanediol, which activates androgen receptors. Elucidating details about the hydride reduction of 5α-DHT by 3α-HSD and the environment around the active site of the enzyme could lead to the development of effective drugs for the treatment of prostate cancer. In this study, the X-ray crystal structure of human 3α-HSD type 3 was comprehensively evaluated. Moreover, molecular dynamics (MD) simulations and hybrid ONIOM-type quantum mechanics/molecular mechanics (QM/MM) calculations were performed using a large QM region (maximum 232 atoms). It was determined that the reaction proceeded in a single step without the formation of an alkoxide ion owing to the direct hydride reduction of the substrate by nicotinamide adenine dinucleotide phosphate (NADPH) and concerted proton transfer by Tyr55 and Lys84. Noncovalent interaction (NCI) analysis highlighted the roles of Tyr216 and Trp227 in 3α-HSD. Specifically, Tyr216 assisted the reaction by π/π interactions with the neighboring nicotinamide ring of NADP(H), whereas Trp227 played an important role in recognition of the size of the substrate by CH/π interactions.

Responses of sex steroid hormones to different intensities of exercise in endurance athletes.

Previous studies have shown that acute exercise elevates sex steroid hormone concentrations in rodents and that sprint exercise increases circulating testosterone in healthy young men. However, the effect of different exercise intensities on sex steroid hormone responses at different levels of physical fitness is still unclear. In this study, we compared circulating sex steroid hormone responses at different exercise intensities in athletes and non-athletes. Eight male endurance athletes and 11 non-athletes performed two 15 min sessions of submaximal exercise at 40 and 70% peak oxygen uptake (V̇(O2peak)), respectively, and exercised at 90% V̇(O2peak) until exhaustion. Venous blood samples were collected during the last minute of each submaximal exercise session and immediately after exhaustion. Acute exercise at 40, 70 and 90% V̇(O2peak) induced significant increases in serum dehydroepiandrosterone (DHEA) and free testosterone concentrations in non-athletes. On the contrary, only 90% V̇O2 peak exercise led to an increase in serum DHEA and free testosterone concentrations in athletes. Serum 5α-dihydrotestosterone concentrations increased with 90% V̇(O2peak) exercise in both athletes and non-athletes. Additionally, serum estradiol concentrations were significantly increased at moderate and high exercise intensities in both athletes and non-athletes. These results indicate that in endurance athletes, serum sex steroid hormone concentrations, especially serum DHEA and 5α-dihydrotestosterone concentrations, increased only with high-intensity exercise, suggesting that different responses of sex steroid hormone secretion are induced by different exercise intensities in individuals with low and high levels of physical fitness. In athletes, therefore, high-intensity exercise may be required to increase circulating sex steroid hormone concentrations.

Reductive 17beta-hydroxysteroid dehydrogenases which synthesize estradiol and inactivate dihydrotestosterone constitute major and concerted players in ER+ breast cancer cells

The reductive 17β-hydroxysteroid dehydrogenases which catalyze the last step in estrogen activation for estrogen dependent breast cancer cells were studied. Their biological function and the effects of their knockdown for cancer cell proliferation were demonstrated. The multidisciplinary study involves enzyme catalysis, sex-hormone and cell cycle regulation, as well as cell proliferation in breast cancer cells. Reductive 17β-HSD1, -7 and -12 were studied in the main breast cancer epithelial cells MCF-7 and T47D. Modification of estradiol and 5α-dihydrotestosterone concentrations was monitored by ELISA assay while corresponding cell viability measured by MTT assay. Cell cycle was determined by flow cytometry. Dual activity of estradiol activation and 5α-dihydrotestosterone reduction by 17β-HSD1 and -7 was critical for breast cancer cell (T47D and MCF-7) viability. Cell viability was decreased by 35.8%±1.6% in T47D cells after simultaneously knocking down 17β-HSD1 and -7. MCF-7 cell viability was decreased by 29.3%±4.2% using a combination of siRNAs and inhibitors. By knocking down 17β-HSD7, we have provided the first demonstration of the significant role of this enzyme in the stimulation of breast cancer cell viability as a result of its high activity on androgen reduction with positive feedback on estradiol production. A further decrease in cell viability was not observed with additional knockdown of 17β-HSD12 after 17β-HSD1 and 7. Breast cancer cell cycle progression was impeded to enter the S phase from G0–G1 after knocking down 17β-HSD1 and -7. In summary, this is the first demonstration that the dual activity in estrone activation and 5α-dihydrotestosterone reduction are the functional basis of reductive 17β-HSDs in breast cancer cells. 17β-HSD1 and -7 are principal reductive 17β-HSDs and major players in the viability of estrogen-dependent breast cancer cells. Combined targeting of these enzymes may be potential for molecular therapy of such cancer.

Expression changes and regulation of AR and IGF-1 in PC3 prostate cancer cells treated with sexual hormones and flutamide

The study aims to investigate the changes and regulation of androgen receptor and insulin-like growth factor-1 in the PC3 prostate cells treated with 5α-dihydrotestosterone, estrone, and flutamide. The PC3 cells were cultured and treated with 5α-dihydrotestosterone, estrone, and flutamide. Immunocytochemistry and Western blot were used to detect the expression of androgen receptor and insulin-like growth factor-1. The androgen receptor expression was analyzed by Western blot and optic density scan in the presence or absence of various kinase inhibitors. The statistical calculations were performed with the statistics-analyzing software package SPSS 13.0. A P <0.05 was considered statistically significant. The concentrations of 5α-dihydrotestosterone and flutamide could almost not change the expression of androgen receptor and insulin-like growth factor-1 in PC3. But, the concentrations of estrone could increase the expression of androgen receptor and insulin-like growth factor-1 when PC3 cells are exposed to the studied concentration at various times. The expression of androgen receptor was regulated by the inhibitor of signal pathways of PI3, MEK1/2, and JUK. The expressions of androgen receptor and insulin-like growth factor-1 were influenced by estrone and were not influenced by 5α-dihydrotestosterone and flutamide in PC3 cells. And, the expression of androgen receptor was regulated by multiple signal pathways.

Seized designer supplement named “1-Androsterone”: Identification as 3β-hydroxy-5α-androst-1-en-17-one and its urinary elimination

New analogues of androgens that had never been available as approved drugs are marketed as “dietary supplement” recently. They are mainly advertised to promote muscle mass and are considered by the governmental authorities in various countries, as well as by the World Anti-doping Agency for sport, as being pharmacologically and/or chemically related to anabolic steroids. In the present study, we report the detection of a steroid in a product seized by the State Bureau of Criminal Investigation Schleswig-Holstein, Germany. The product “1-Androsterone” of the brand name “Advanced Muscle Science” was labeled to contain 100 mg of “1-Androstene-3b-ol,17-one” per capsule. The product was analyzed underivatized and as bis-TMS derivative by GC–MS. The steroid was identified by comparison with chemically synthesized 3β-hydroxy-5α-androst-1-en-17-one, prepared by reduction of 5α-androst-1-ene-3,17-dione with LS-Selectride (Lithium tris-isoamylborohydride), and by nuclear magnetic resonance. Semi-quantitation revealed an amount of 3β-hydroxy-5α-androst-1-en-17-one in the capsules as labeled. Following oral administration to a male volunteer, the main urinary metabolites were monitored. 1-Testosterone (17β-hydroxy-5α-androst-1-en-3-one), 1-androstenedione (5α-androst-1-ene-3,17-dione), 3α-hydroxy-5α-androst-1-en-17-one, 5α-androst-1-ene-3α,17β-diol, and 5α-androst-1-ene-3β,17β-diol were detected besides the parent compound and two more metabolites (up to now not finally identified but most likely C-18 and C-19 hydroxylated 5α-androst-1-ene-3,17-diones). Additionally, common steroids of the urinary steroid profile were altered after the administration of “1-Androsterone”. Especially the ratios of androsterone/etiocholanolone and 5α-/5β-androstane-3α,17β-diol and the concentration of 5α-dihydrotestosterone were influenced. 3α-Hydroxy-5α-androst-1-en-17-one appears to be suitable for the long-term detection of the steroid (ab-)use, as this characteristic metabolite was detectable in screening up to nine days after a single administration of one capsule.

Do mothers regulate facultative and obligate siblicide by differentially provisioning eggs with hormones?

We examined androgens in clutches of two booby species that differ in their sibling conflict. Blue-footed booby Sula nebouxii chicks show an aggression-submission relationship, aggression is normally moderate and siblicide is facultative. Brown booby Sula leucogaster chicks show an aggression-aggression relationship, aggression of both chicks can be relentless and siblicide is obligate. The parental favoritism hypothesis predicts that egg mass, yolk mass and yolk androgens should decline with laying order less in the blue-footed booby than in the brown booby, to promote the survival of the former's junior chick. The eggs of the blue-footed booby had higher yolk concentrations of 5α-dihydrotestosterone (DHT) and lower concentrations of testosterone (T); both species had similarly high yolk concentrations of androstenedione (A). Intra-clutch variation in yolk DHT, T and A failed to support our predictions. In both species, first and second eggs showed similar concentrations of all three hormones and were of similar size, although in the blue-footed booby (only) yolk masses declined with laying order. Brown booby mothers make junior chicks vulnerable to siblicide by hatching them 5 d after their broodmates, but not by differential allocation of egg androgens or nutrients. Blue-footed booby mothers appear to prepare junior chicks for thriving in a subordinate non-provocative role by hatching them 4 d after their broodmates and providing them with 10% less yolk. To orchestrate agonism within the brood, these boobies may rely more on hatch intervals and yolk provision than on androgens.

Inhibition of 5α-reductase in the rat prostate by Cimicifuga racemosa

Objectives Prostate cancers and many thereof derived cell lines, as the LNCaP cells, grow androgen-dependent. In vivo testosterone is locally converted by 5α-reductase to 5α-dihydrotestosterone (5α-DHT) which is the major androgenic principle in prostates and seminal vesicles. The occurrence of prostate cancer and growth of LNCaP cells can be effectively inhibited by finasteride, a synthetic 5α-reductase inhibitor and by a black cohosh ( Cimicifuga racemosa, CR) extract. In the present contribution we tested whether the aqueous/ethanolic C. racemosa extract BNO 1055 contains 5α-reductase inhibitors. Methods Immature 24-day-old male rats were fed with testosterone (T)-containing food and injected with 30 mg CR BNO 1055 or 0.5 mg finasteride for 5 days. Average daily T-uptake was 39 mg/animal. Other animals remained untreated or received vehicle injections only. Results In comparison to totally untreated rats the testosterone treatment increased weight of prostates and seminal vesicles 3–5-fold and this proliferation was largely and equipotently inhibited by finasteride and CR BNO 1055. 5α-Dihydrotestosterone concentrations in prostate tissue extracts were also reduced by both compounds and the testosterone-upregulated androgen receptor and insulin like growth factor I gene expression inhibited in the seminals vesicles. Conclusion Taken together, these results indicate that the CR extract BNO 1055 contains one or more potent 5α-reductase inhibitors which may make this extract suitable for the prevention and treatment of prostate cancer and possibly of benign prostate hyperplasia (BPH).

Sexual Dimorphism in Numbers of Vasotocin-Immunoreactive Neurons in Brain Areas Associated with Reproductive Behaviors in the Roughskin Newt

Vasotocin (VT) and vasopressin control many endocrine and neuroendocrine functions, including the regulation of reproductive behaviors. In the roughskin newt (Taricha granulosa), VT administration can enhance courtship behaviors in males and egg-laying behaviors in females. This study used immunohistochemistry to investigate whether there are sex differences in VT in specific brain areas, and whether these differences persist in nonbreeding animals. Numbers of VT immunoreactive (ir) cell bodies were counted in males and females collected in February, April, June, and August. Radioimmunoassay of plasma samples confirmed that testosterone and 5α-dihydrotestosterone concentrations were higher in males than females, and that 17β-estradiol concentrations were higher in females than males. In 11 brain areas, no sexual or seasonal differences in the number of VTir cells were found. But in 3 brain regions—the bed nucleus of the stria terminalis (BNST), the nucleus amygdalae dorsolateralis (AMYG), and the anterior preoptic area (aPOA)—there were significantly greater numbers of VTir cells in males than in females, and these differences did not change seasonally. In the aPOA, an area important to male sex behaviors, the sexual dimorphism in VTir was particularly pronounced. In four brain regions, there were significantly greater numbers of VTir cells in females than males, but only in specific seasons. In April-collected (breeding) animals, more VTir cells were found in females than in males in the populations of VT cells within the pars dorsalis hypothalami and ventromedial hypothalamus, brain regions frequently associated with stress responses and female mating behaviors. In August-collected (nonbreeding) animals, more VTir cells were found in females than in males, in the region of the bed nucleus of the decussation of the fasciculus lateralis telencephali and in the nucleus visceralis superior, nucleus isthmi region. Significantly greater numbers of VTir cells were observed in the magnocellular preoptic area of males and females collected in February. These results indicate that the functional interactions between gonadal steroid hormones and VT are complex and appear to involve site-, sex-, and season-specific regulatory mechanisms. Furthermore, it seems likely that populations of VT neurons in the BNST, AMYG, and aPOA are involved in regulating male-specific behaviors, and that the VT neurons in the pars dorsalis hypothalami/ventromedial hypothalamus may be involved in female-specific behaviors.

Effects of Oxytocin and Prostaglandin F 2α on Androgen Production of Adult Rat Testis In Vivo

The relationships among androgens, oxytocin, and prostaglandin F 2α (PGF 2α), all of which are produced in Leydig cells, are not known. In this study, the effects of administration of oxytocin on the production of androgens and PGF 2α, or of PGF 2α on the production of androgens and oxytocin, in adult male rats were investigated. First, 100 ng of oxytocin or 50 μg of PGF 2α was injected into a testis twice daily for 4 days. Some rats were injected with 10 IU of human chorionic gonadotropin (hCG) through the external jugular vein 1.5 h before being sacrificed. hCG was given to stimulate the production of androgens. Rats were sacrificed and testicular hormone concentrations were measured. Oxytocin decreased testosterone concentration and increased concentrations of 5α-dihydrotestosterone (5α-DHT) and PGF 2α. PGF 2α decreased testosterone concentration and tended to increase 5α-DHT concentration, but had no effect on oxytocin. The injection of hCG increased the concentration of testosterone and 5α-DHT, but the effects of oxytocin or PGF 2α on androgen production were similar whether hCG was injected or not. These results indicate that in adult rat testis, oxytocin and PGF 2α promote the metabolism of testosterone, and suggest that the action of oxytocin is mediated through PGF 2α.

Effects of in Utero and Lactational 2,3,7,8-Tetrachlorodibenzo-p-dioxin Exposure on Responsiveness of the Male Rat Reproductive System to Testosterone Stimulation in Adulthood

Previous studies strongly suggested that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) may cause incomplete imprinting of the male reproductive system, i.e., that in utero and lactational exposure to TCDD may alter the responsiveness of sex organs to steroids in adulthood. To test this hypothesis, male rats born to dams dosed with 0.7 μg TCDD/kg or vehicle on Gestation Day 15 were castrated at 63 days of age and implanted with graded lengths of Silastic capsule(s) containing crystalline testosterone. Resultant plasma testosterone concentrations ranged from castrate to about fourfold higher than physiological. Male reproductive organs which are imprinted by exposure to perinatal androgens and which are highly responsive to androgen stimulation in adulthood were assessed 3 weeks later. Ventral prostate weight and protein content in TCDD-exposed rats were significantly less responsive to testosterone regardless of the amount implanted. These decreases were not secondary to alterations in plasma or prostate testosterone or 5α-dihydrotestosterone concentrations in adulthood, none of which was affected by TCDD. In contrast to its effects on ventral prostate weight and protein, TCDD had no effect on responsiveness to testosterone as measured by ventral prostate DNA content; seminal vesicle weight, protein content, or DNA content; penis weight; or plasma LH concentrations. We conclude that in utero and lactational TCDD exposure inhibits imprinting of ventral prostate weight and protein but does not result in a universal inhibition of imprinting. Androgen responsiveness of the prostate is uniquely sensitive to in utero and lactational TCDD exposure and provides a model to study the mechanism by which exposure to TCDD during fetal and early postnatal development modulates hormone-mediated responses in adulthood.

In utero and lactational exposure of male rats to 2,3,7,8-tetrachlorodibenzo- p-dioxin : I. Effects on androgenic status

When administered in overtly toxic doses to postpubescent rats, 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) produces a variety of adverse effects on the male reproductive system including a decrease in plasma androgen concentrations. If such an androgenic deficiency were produced prenatally and/or early postanatally it could potentially impair male reproductive function by disrupting the development of sex organs and/or causing incomplete sexual differentiation of the central nervous system. To determine whether TCDD can reduce androgen concentrations perinatally and/or impair androgen-dependent perinatal development, pregnant Holtzman rats were treated with 1.0 μg TCDD/kg or vehicle on Day 15 of gestation. Plasma testosterone concentrations in fetal males were significantly reduced by TCDD on Gestation Days 18 through 21. The surge in plasma testosterone concentrations shortly after birth was also significantly reduced, as was anogenital distance, an androgen-dependent parameter. To further investigate the effects of perinatal TCDD exposure on the male reproductive system, rats born to dams given TCDD (0.064, 0.16, 0.40, or 1.0 μ/kg, po) or vehicle on Day 15 of gestation were evaluated from birth through sexual maturation. This report describes their growth, physical development, and androgenic status (i.e., androgen concentrations and androgen-dependent structures and functions); effects on spermatogenesis, testicular histology, sexual behavior, and fertility are reported separately. There was little evidence that TCDD caused maternal toxicity. Signs of overt toxicity in offspring were limited to an 8% reduction in live births (highest dose only) and to decreases in body weight gain and feed consumption (two highest doses only) which disappeared by early adulthood. With respect to androgenic status, maternal TCDD doses as low as 0.16 μg/kg produced significant dose-related decreases in the anogenital distance of 1- and 4-day-old males, delays in testicular descent, and decreases in seminal vesicle and ventral prostate weights. The reductions in organ weights were observed when rats were at the juvenile, pubertal, postpubertal, and mature stages of sexual development. Plasma testosterone and 5α-dihydrotestosterone concentrations tended to be reduced at these times (though not significantly), while plasma luteinizing hormone concentrations were generally unaffected. Collectively, these results demonstrate that perinatal TCDD exposure alters the androgenic status of male rats from the fetal stage into adulthood, and that TCDD can affect androgenic status without causing overt toxicity. In rats, the male reproductive system appears to be more sensitive to the toxic effects of in utero and lactational TCDD exposure than any other organ or organ system studied thus far.

Intranuclear androgen concentrations in facial skin

The concentrations of 5α-dihydrotestosterone (DHT) and testosterone were measured by radioimmunoassay (RIA) in the crude nuclear and cytoplasmic fractions of facial skin containing large sebaceous glands. The data obtained were compared with those obtained with specimens from non-target areas. The intranuclear levels of DHT and testosterone in facial skin were 0.03 ± 0.3 pg/μg DNA and 0.35 ± 0.03 pg/μg DNA, respectively. They were comparable to the respective levels in genital skin. By contrast, both androgens were below detection by RIA in non-target skin. There was no significant difference between men and women with respect to the intranuclear androgen levels in facial skin. These findings support the view that the sebaceous gland is a typical androgen target organ irrespective of sex.

Assessment of the Critical Level of Androgen for Growth Response of Transplantable Human Prostatic Carcinoma (PC-82) in Nude Mice

The androgen dependent prostatic carcinoma of human origin, PC-82, was used as a model system to investigate the effect of various levels of androgen on the growth of prostatic tumor tissue. Plasma testosterone levels in mice were correlated to tumor growth and intratumor concentrations of testosterone and 5α-dihydrotestosterone. PC-82 tumor burden remained stable at plasma testosterone levels of 0.8 nmol/1., whereas tumor growth occurred at higher levels and tumor regression was observed at lower plasma levels. This critical level of testosterone corresponded with intratumor testosterone and 5α-dihydrotestosterone concentrations of six to 10 and three to four pmol/gm. tissue, respectively, which are significantly above the levels found in castrated non-supplemented animals (3.1 and 1.4 pmol/gm. respectively). This indicates that remaining concentrations of dihydrotestosterone, which amount to two to three times the castrate level, are not stimulatory for tumor growth in the model of the androgen dependent PC-82 tumor.

Androgenic deficiency in male rats treated with perfluorodecanoic acid

Effects of perfluorodecanoic acid (PFDA, 20–80 mg/kg, ip) on the androgenic status of sexually mature male rats were investigated 7 days after treatment. PFDA decreased plasma androgen concentrations in a dose-dependent fashion with an ED50 of approximately 30 mg/kg. The highest dose of PFDA decreased plasma testosterone and 5α-dihydrotestosterone concentrations to 12 and 18%, respectively, of ad libitum-fed control (ALC) values. Secondary to the decreased plasma androgen concentrations were dose-related decreases in the weights and epithelial heights of accessory sex organs. Results from pair-fed control (PFC) rats show that hypophagia in PFDA-treated rats was not a major cause of the low plasma androgen concentrations. When rats were castrated and implanted with testosterone-containing capsules, PFDA-treated and ALC rats had similar plasma testosterone concentrations and secondary sex organ weights. Therefore, the androgenic deficiency in intact PFDA-treated rats does not result from increased plasma clearance of androgens. Rather, PFDA must cause the androgenic deficiency by decreasing the secretion of testosterone from the testis. The decrease in testosterone secretion does not appear to result from a decrease in plasma luteinizing hormone (LH) concentrations, because plasma LH concentrations were not significantly altered by PFDA treatment. This finding suggests that PFDA treatment decreases testicular responsiveness to LH stimulation. The observation that PFDA treatment reduced the secretion of testosterone by testes stimulated in vitro with the LH analog human chorionic gonadotropin demonstrates that this is the case. In addition, since plasma LH concentrations did not increase in response to the low plasma androgen concentrations in PFDA-treated rats, we suggest that PFDA disrupts the normal feedback relationship which exists between plasma androgen and LH concentrations.

The equivocal presence of nuclear androgen binding proteins in mammalian spermatids and spermatozoa

The presence of nuclear androgen binding proteins measured by nuclear androgen exchange in rat spermatids arid spermatozoa was re-examined. Specific binding was observed to be related to less dense contaminating particles when sonicated testes were fractionated by isopcynic centrifugation through a 40–61% Nycodenz linear gradient. No specific binding was observed in a pure preparation of epididymal spermatozoa collected by retrograde perfusion of the cauda epididymidis, even when a nuclear exchange assay of superior sensitivity [17] was used. Contamination could easily be induced by adding prostatic tissue to epididymal spermatozoa prior to sonication. Despite this strong evidence that the measure of nuclear androgen receptors by nuclear exchange in germ cells is artefactual, the persistence of high endogenous concentrations of 5α-dihydrotestosterone and 5α-diols (but not testosterone) in spermatozoa of castrated rats argues for the opposite conclusion.

Radioimmunological determinations of concentrations of six C 21, C 19 and C 18 steroids during the reproductive cycle of female Artemia SP. (Crustacea: Anostraca)

1. 1. Progesterone, pregnenolone, 5α-dihydro testosterone, testosterone, estrone and estradiol were measured by radioimmunoassay in purified total body extracts of adult female Anemia during the vitellogenic cycle. 2. 2. Progestagens were present in high amounts (20–30 ng/g) between the vitellogenic cycles while estrogen concentrations had peak values during vitellogenesis (mean values of 269 pg/g and 2720 pg/g for estrone and estradiol, respectively). 3. 3. When testosterone concentrations were lowest (144 pg/g), concentrations of 5α-dihydrotestosterone increased up to 1190 pg/g.

Testicular responsiveness to human chorionic gonadotrophin during transient hypogonadotrophic hypogonadism induced by androgenic/anabolic steroids in power athletes

Serum concentrations of testosterone, 17-hydroxyprogesterone, estradiol and several other unconjugated and sulphated steroids were analyzed before and after a single dose of hCG in 6 power athletes, who had used high doses of testosterone and anabolic steroids for 3 months. The study was carried out 3 weeks after cessation of drug use, but the study subjects were still characterized by hypogonadotrophic hypogonadism. The mean concentrations of serum LH and FSH were 2.6 ± 0.3 and 1.1 ± 0.03 mIU/ml (mean ± SEM), respectively, and the concentrations of several precursors and metabolites of testosterone were lower than those before drug use. In contrast, circulating concentrations of steroid sulphates were not decreased, with the exception of dehydroepiandrosterone sulphate. After hCG injection serum testosterone and 5α-dihydrotestosterone concentrations increased significantly, whereas no increases in estradiol and 17-hydroxyprogesterone concentrations were observed. These results demonstrate that during transient hypogonadotrophism in adult men, the testicular responsiveness to a single injection of hCG is similar to that in prepubertal boys without any sign of steroidogenic lesion at the 17,20-desmolase step. Therefore, the appearance of the possibly estradiol-mediated inhibition at the level of C 21-steroid side-chain splitting in testosterone biosynthesis seems to be dependent on priming by gonadotrophins.

A 250-kilodalton cellular protein is induced by progestins in two human breast cancer cell lines MCF 7 and T 47D

We have studied the effect of R5020, a synthetic progestin, on the biosynthesis of cellular proteins extracted from the MCF 7 and T 47D human breast cancer cells, using gel electrophoresis. R5020 stimulates the synthesis, as measured after ( 35S)-methionine labelling, and the accumulation, as shown by silver staining, of a protein of molecular weight ≅ 250,000. The increase of the labelled 250-kilodalton protein was rapid (3 hours) and after 3 days this protein represented ≅ 6 % of the total cellular proteins (≅1 μg/150,000 cells). The induction of the 250-kilodalton protein was obtained by physiologically active concentrations of several progestins and high concentrations of 5α-dihydrotestosterone but not by estradiol or dexamethasone. It was inhibited by R486, a progestin antagonist, but not by flutamide, an androgen antagonist. These results indicate a mediation by the progesterone receptor. The 250-kilodalton protein appears to be an excellent probe to study in cell culture the mechanism of action of progestin on human cells.

Short-term response of testosterone, dihydrotestosterone, 5 alpha-androstane-3 beta, 17 beta-diol, testosterone-glucosiduronate and estradiol-17 beta as measured in the spermatic vein of human male subjects after infusion of gonadotropins.

In 8 male subjects with normal testicular function, blood was drawn from the left spermatic vein and from the right cubital vein before and during an infusion of 4,000 IU human chorionic gonadotropin (hCG) (preceded by a bolus of 1,000 IU) or of 500 IU hCG plus human menopausal gonadotropin (hMG), respectively, within 30 min. Testosterone levels in the spermatic vein blood increased rapidly up to 518 or 215%, respectively. An increase of estradiol-17 beta and of 5 alpha-dihydrotestosterone concentrations in spermatic vein blood was observed only in 1 and 2 subjects, respectively. It was shown that the human testicle releases also 5 alpha-androstane-3 alpha, 17 beta-diol and testosterone-glucosiduronate. Both steroids did not respond to the short-term infusion of gonadotropins. The same holds true for all five steroids measured in peripheral vein blood.

Reduction of androstenedione by skin in vitro and serum levels of gonadotrophins and androgens in men with hypospadias.

The reduction of 4-[1,2-3H]androstene-3,17-dione (androstenedione) in vitro by scrotal skin was measured in samples from nine men (16--34 years old) with hypospadias and from ten male control subjects. The reduction of androstenedione was also studied in axillary and upper arm skin of seven control subjects. Androstenedione was reduced to material with chromatographic characteristics of 5 alpha-androstane-3,17-dione and to 3 alpha- and 3 beta-hydroxy-5 alpha-androstan-17-one. No difference in 5 alpha-reductase activity (defined as the sum of these three metabolites formed) was found in scrotal skin from hypospadic and control men. The mean concentration of 5 alpha-dihydrotestosterone in serum from men with hypospadias was lower than that in serum from control subjects (P less than 0.01). The mean ratio of the serum concentrations of testosterone and 5 alpha-dihydrotestosterone was higher in hypospadic men than in control subjects (P less than 0.05). No differences between the two groups were found in the mean serum concentrations of LH, FSH, prolactin, dehydroepiandrosterone, androstenedione, testosterone or testosterone-binding globulin.