Male patients with terminal renal failure exhibit low serum levels of antimüllerian hormone

Male reproductive function is impaired during end-stage renal disease (ESRD). Disturbance of the hypothalamic-pituitary-gonadal axis, and therefore the regulation of sex hormones, is one of the major causes. Our focus was to include antimüllerian hormone (AMH) and inhibin B concentrations. Twenty male patients on hemodialysis, median age 40 (26–48) years, were analyzed for follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, sex hormone-binding globulin (SHBG), testosterone, estradiol, AMH and inhibin B levels. We used 144 proven fertile men, median age 32 (19–44) years as a control group and analyzed differences using multiple linear regression. Males with ESRD demonstrated higher mean values for prolactin, 742 versus normal 210 mIE l⁻¹ (95% confidence interval (CI): 60.3, 729), LH, 8.87 versus normal 4.5 IE l⁻¹ (95% CI: 2.75, 6.14), and estradiol 89.7 versus normal 79.0 pmol l⁻¹ (95% CI: −1.31, −0.15). Mean value for AMH was lower, 19.5 versus normal 47.3 pmol l⁻¹ (95% CI: −37.6, −11.6). There were no differences found for FSH, SHBG, inhibin B and testosterone. The most important difference was found for AMH, a marker of Sertoli cell function in the testes, which decreased by close to 60% when compared with controls. Combined with an increase in LH, these findings may indicate a dysfunction of Sertoli cells and an effect on Leydig cells contributing to a potential mechanism of reproductive dysfunction in men with ESRD.     

Effect of kisspeptin challenge on testosterone and inhibin secretion from in vitro testicular tissue of adult male rhesus monkey (Macaca mulatta)

Kisspeptin expression has been found in gonads but a direct role of kisspeptin in reproduction is not known. The objective of this study was to find a dose and time related effect of kisspeptin on testicular hormones secretion of adult male rhesus monkey (n = 5). Kisspeptin (1, 10, 100, 1000 pm ) was incubated to a culture of testes (100 mg fragments) of male rhesus monkey and medium for hormone (testosterone and inhibin) measurement was collected after 30, 60 and 120 min. 10 IU hCG (180 min) and 50 ng FSH (60 and 120 min) were incubated to the culture for checking testicular cells ability to secrete hormones in vitro. Kisspeptin did not significantly (P < 0.05) increase the testosterone and inhibin levels at any dose. However, one way anova at pooled doses showed an increase in testosterone levels and paired t‐test at pooled doses showed inhibin decrease after 120 min of incubation suggesting an independent effect of time. hCG and FSH significantly (P < 0.05) increased hormone concentration compared to the basal groups. We concluded that kisspeptin has no role in testicular regulation related to testosterone and inhibin release but kisspeptin may have other roles in testicular regulation.     

Relationships between serum hormone levels and semen quality among men from an infertility clinic

Participation rates in epidemiologic studies on semen quality are generally very low, raising concerns as to the potential for selection bias. Since hormones both initiate and maintain spermatogenesis, they may serve as surrogates of semen quality in epidemiologic studies. For this reason, in the present study, we explored the influence and predictive ability of reproductive and thyroid hormones on semen quality among men who were partners in an infertile couple. Between 1999 and 2003, 388 men were recruited from Massachusetts General Hospital Andrology Laboratory for clinical evaluation of fertility status. Fresh semen samples were assessed for quality (concentration, motility and morphology) and the serum levels of hormones, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), inhibin B, sex hormone-binding globulin (SHBG), testosterone, free androgen index, free T4, total T3, and thyroid-stimulating hormone (TSH), were measured. Multiple logistic regression revealed increased odds for below-reference sperm concentration and morphology in men with increased FSH, and decreased odds for below-reference sperm concentration and motility in men with increased inhibin B. When FSH and inhibin B were divided into quintiles, the relationships with sperm concentration showed evidence of a threshold value. However, the ability of specific FSH (10 IU/L) and/or inhibin B (80 pg/mL) cutoff values to predict semen quality was lower than in previous reports. In multiple linear regression analysis, FSH and LH were inversely associated with sperm concentration, motility, and morphology. Inhibin B and free T4 were positively associated with sperm concentration, while there was a suggestive positive association between testosterone and sperm motility. In conclusion, we have found that FSH, LH, inhibin B, testosterone and free T4 levels are associated with human semen parameters. Additional consideration should be given to the utility of serum hormone levels as a surrogate for semen quality in epidemiologic studies in which the collection of semen is difficult due to logistical and/or volunteer rate constraints.     

Nature and Mechanisms of Action of Inhibin: Perspective in Regulation of Male Fertility

Inhibin extracted from human seminal plasma and from rete testis fluid is a protein substance. Two forms of inhibin exist in RTF and each has a different molecular weight. The species of higher molecular weight systematically yields a product of lower molecular weight during chromatography. This phenomenon could represent depolymerization of the molecule, an associated transport protein or alternatively a precursor form of inhibin.
The inhibin preparations utilized selectively lowered the levels of FSH as assessed both in vivo and in vitro . This action was not totally specific since increasing doses of inhibin also produced a lowering of the levels of LH. In contrast, these preparations did not influence the secretion of TSH, growth hormone or prolactin in vivo or in vitro .
A direct effect of inhibin on pituitary cells has been clearly established by demonstrating a reduction in the release of FSH in response to GnRH and its synthesis in the pituitary cells. Additional direct effects on the hypothalamus and on gametogenesis in the testis remain to be excluded. On the basis of selective effects of inhibin on FSH secretion, one could envisage the utilization of this hormone as an antifertility agent.     

Serum inhibin levels after administration of hCG

Administration of hCG to normal healthy men caused 40 fold increase in circulating levels of inhibin at 24 hr. FSH levels decreased between 72-120 hr of hCG injection. Although, testosterone levels were maintained at higher levels during hCG therapy for more than 10 days, inhibin and FSH levels returned back to pretreatment levels, indicating involvement of hCG in the regulation of circulating levels of inhibin.     

Clinical study of hypogonadotropic hypogonadism

Clinical study of eight cases of hypogonadotropic hypogonadism was performed. These cases consisted of five prepubertal cases and three postpubertal cases induced by prolactin-producing hypophyseal tumor. The former five cases had the chief complaints of incomplete development of their external genitalia. The chief complaints in three postpubertal cases were decreased libido in two and infertility in one. The average testicular volumes were 7.8 ml and 20 ml in prepubertal and postpubertal cases, respectively. The basal levels of luteinizing hormone (LH) were within the normal limit in most cases and follicle stimulating hormone (FSH) were low in most cases. There were no differences between the levels of these hormones in prepubertal cases and those in postpubertal cases. The range of basal level of prolactin in blood was 92 mg/ml to 1,070 ng/ml in the postpubertal cases. The basal level of testosterone in blood was low in all cases. Most cases had rather good responses of LH and FSH after the administration of luteinizing hormone releasing hormone. The plasma level of testosterone was elevated after the administration of human chorionic gonadotropin (hCG) in most cases. The appearance of sperm in the semen was observed after the hCG therapy in only one of the prepubertal cases. On the other hand, all the postpubertal cases showed almost normal findings in semen analysis after hormone therapy.     

Inhibin interaction with LHRH receptors at the pituitary level

In order to investigate whether inhibin could modulate the action of luteinizing hormone releasing hormone (LHRH), the in vitro effect of inhibin of LHRH bindings to the pituitaries from intact adult male rats was studied. The inhibin preparations suppressed the binding of labeled LHRH to pituitary receptors in a dose-related manner. In vivo administration of inhibin decreased the pituitary LHRH receptor concentration, with an apparent increase in the affinity of these receptors. A dose-related decrease was observed in serum follicle stimulating hormone (FSH) levels in the same group whereas the serum luteinizing hormone (LH) levels remained unaltered. There may be a direct action of inhibin at the pituitary level to suppress FSH levels specifically.     

Prolactin, corticotropin, and gonadotropin concentrations following thermal injury in adults

The concentration of serum prolactin (PRL), plasma corticotropin (ACTH), serum follicle stimulating (FSH), and luteinizing (LH) hormones were measured in 28 adult burned patients (25 males and three females). Morning and night determinations were performed for each hormone. Serum PRL was elevated in males up to the fourth week after the thermal injury. Plasma ACTH increased significantly on the second day postburn and returned gradually to normal on the fifth; serum FSH and LH increased on day 1, then decreased significantly on day 2 and remained low for about 2 weeks. In females, while PRL increased significantly, the gonadotropins were slightly elevated and the ACTH remained within normal limits for the 3 days during which it was possible to study these patients. In all subjects the circadian rhythm of the four measured hormones showed significant variations from the normal pattern.     

Differential patterns of inhibin secretion in response to gonadotrophin stimulation in normal men

Inhibin B is produced by the testis, and its constituent alpha and beta B subunits have been localized immunohistochemically to Leydig as well as Sertoli cells in both rodent and human testes. Whether Leydig cells contribute to circulating inhibin B concentrations, however, is uncertain. We have investigated this by selectively stimulating Leydig and Sertoli cells with hCG and FSH, respectively. The study was a randomized crossover trial, investigating responses to 225 IU recombinant FSH or 3000 IU hCG administered s/c 4-6 weeks apart. Ten normal men were recruited to participate. Blood was taken twice before treatment and after 8, 24, 48, 72 and 96 h. Serum was assayed for FSH, LH and testosterone by radioimmunoassay (RIA); inhibin B and pro-alpha C inhibin forms by ELISA. Administration of hCG, but not FSH, caused a rapid increase in blood testosterone levels, which reached a maximum after 72 h (22.2 +/- 2.7-50.1 +/- 4.5 nmol/L, p < 0.001). Inhibin B concentrations in blood were unchanged following either treatment. Conversely, pro-alpha C concentrations increased following both treatments. FSH administration resulted in a gradual increase in pro-alpha C concentrations (369 +/- 18 pg/mL pre-treatment to 453 +/- 33 pg/mL after 96 h, p=0.013). Administration of hCG resulted in a more rapid response, with pro-alpha C concentrations rising from 384 +/- 23 pg/mL pre-treatment to a peak at 48 h of 535 +/- 45 pg/mL (p=0.007). This response was more rapid than that of testosterone. These results demonstrate that adult human Leydig, as well as Sertoli, cells secrete inhibin alpha subunit in response to gonadotrophin stimulation but provide no evidence for the secretion of inhibin B from Leydig cells. The lack of change in inhibin B secretion in response to FSH suggests that more prolonged or intense stimulation of Sertoli cells may be required for secretion of the dimeric form.     

Hormonal and seminal evaluation of Leydig cell tumour patients before and after orchiectomy

Seven patients (aged 25-38 years) were admitted because of mono- or bilateral gynaecomastia. Plasma levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, testosterone, 17-beta-estradiol, delta4-androstenedione, dehydropiandrosterone sulphate (DHEA-S) and 17-OH-progesterone were determined and semen analysis was carried out. FSH and LH levels were also measured after acute LH-RH administration (100 microg intravenously), and testosterone and 17-beta-estradiol were also evaluated after acute human chorionic gonadotrophin (hCG) administration (5000 IU intramuscularly). Testicular echography demonstrated the presence of a solid hypoechoic tumour. Therefore all patients were submitted to hemicastration by orchidofuniculotomy and a benign Leydig cell tumour was diagnosed in the removed testes. Hormonal and semen evaluations were repeated 3, 6, 9 and 12 months after surgery. The data before and after surgery were compared with a control group of 10 age-matched males. Before surgery, patients showed low FSH basal plasma levels; high levels of 17-beta-estradiol and low testosterone levels similar to those after hCG administration. A dyspermia was observed. Unilateral orchidectomy eliminated the autonomous secretion of oestrogen(s) so an increase of LH, FSH and testosterone levels, together with an improvement of spermatogenesis, were obtained.     

Routine hormone load tests are unnecessary in infertile men

A sample of 225 men examined at the Infertility Service Unit of this hospital had spermiograms, standardized in accordance with WHO guide lines, and a hormone stimulation test with injection of gonadotropin releasing hormone, thyrotropin releasing hormone, and ACTH. The serum concentrations of the following hormones were assessed: follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin, oestradiol (E), thyroid stimulating hormone, cortisol, 21-desoxycortisol, 17-hydroxypregnenolone, 17-hydroxyprogesterone, dehydroepiandrosterone, dehydroepiandrosteronesulphate, androstenedione, testosterone (T), and dihydrotestosterone. The results of the spermiograms were found to be related to the concentrations of the following hormones: FSH, LH, T, and E. Thyroid and adrenal function in men without signs of endocrinological diseases failed to influence spermatic parameters.     

The hypothalamus-pituitary-testis axis in boys during the first six months of life: a comparison of cryptorchidism and hypospadias cases with controls

It is inconclusive whether the feedback mechanisms of the hypothalamus-pituitary-testis (HTP) axis are already established in the first 6 months of life, partly due to the dramatic changes in HPT-axis hormone levels over this period. Moreover, it is unclear whether these hormone levels are aberrant in boys with cryptorchidism or hypospadias, and therefore predictive for future fertility. We studied the regulation mechanisms of the HTP axis, and the effect of age, in boys 1–6 months of age. Secondly, we studied testicular function - as reflected by HPT hormones - in newborns with cryptorchidism or hypospadias. Sera from a population sample of infants with cryptorchidism ( n  = 43), hypospadias ( n  = 41) and controls ( n  = 113) were analyzed for inhibin B, anti-Müllerian hormone (AMH), testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH) and sex hormone binding globulin (SHBG). LH, testosterone, non-shbg-bound testosterone (NSBT), and AHM levels showed significant age-related trends. After age-correction, a negative correlation between FSH and inhibin B was observed ( r  = −0.43). The only significant group-differences were lower testosterone and NSBT levels in cryptorchidism cases, with a mean testosterone of 1.8 and 2.6 nmol/L and a mean NSBT of 0.48 and 0.70 nmol/L for cryptorchidism cases and controls, respectively. The higher levels of LH, testosterone, and NSBT in boys born pre-term or with a low birthweight indicate that abnormal prenatal development may determine postnatal testis function. Our results support the hypothesis that the inhibin B – FSH feedback loop is already functional before puberty. The lower testosterone and NSBT levels indicate that disturbed Leydig cell function can already be detected early after birth in cryptorchid boys.     

紫草辅助米非司酮抗早孕对生殖激素的影响

为了探讨紫草辅助米非司酮抗早孕时对早孕妇女血中生殖激素的影响 ,88例早孕妇女随机分成服用米非司酮、紫草、米非司酮加紫草组和空白对照组 ,比较用药前后血人绒毛膜促性腺激素β亚单位 (β-h CG)、卵泡刺激素 ( F SH)、黄体生成素 ( L H)、雌二醇 ( E2 )、孕酮 ( P)和睾酮 ( T)的变化。结果 :单用米非司酮或紫草均对 β-h CG有一定的抑制作用 ,二者合用抑制作用更加明显 ;单用紫草对血中 FSH、 L H有较明显的抑制作用 ,对 E2 、P及 T无明显影响。认为紫草对绒毛功能有一定的影响 ,与米非司酮合用影响更明显 ;紫草对垂体生殖激素有明显的抑制作用。但是否与紫草能提高药物流产效果有关 ,尚需进一步研究。     

Possible role of serum testosterone,gonadotropins and prolactin in patients with premature ejaculation

Premature ejaculation (PE) is the most common male sexual dysfunction. This study aimed to investigate the role of serum testosterone, gonadotropins and prolactin in patients with PE. In a prospective a case‐controlled study, it was conducted on 90 male patients with PE and 90 male healthy participants as controls. Patients were evaluated by Premature Ejaculation Diagnostic Tool (PEDT) and intravaginal ejaculatory latency time (IELT). Patients with mean IELT values ≤60 s and PEDT total scores ≥11 were considered to have PE. Serum levels of total testosterone (TT), free testosterone (FT), follicle‐stimulating hormone (FSH), luteinising hormone (LH) and prolactin (PL) were investigated in patients with PE and controls. There was no statistically significant difference between patients with PE and controls regarding the serum levels of TT, FT, FSH, LH and PL (p value ?.05). There was no significant correlation between the sex hormones levels (TT, FT, FSH, LH and PL) and (age, body mass index (BMI), IELTS and total PEDT scores of the patients; p value ?.05). This study concluded that there was no disturbance in serum levels of testosterone, gonadotropins and prolactin in patients with PE and controls. These hormones could not relate to pathogenesis of PE.     

Circulating levels of inhibin,prolactin, TSH,LH, and FSH in benign prostatic hypertrophy before and after tumor resection

Using specific radioimmunoassays, serum prolactin, TSH, LH, FSH, and inhibin levels were estimated in normal subjects and in patients with benign prostatic hyperplasia (BPH) before and after tumor resection. In the case of BPH, there was a significant rise in inhibin levels as compared to age-matched control groups, whereas LH and FSH levels were decreased significantly. The levels of inhibin and prolactin were significantly reduced after surgery, but no consistent changes in LH, FSH, or TSH levels were noted. The changes observed in hormonal levels in the BPH patients were not related to patient's age or size of the tumor.     

Inhibin B regulating follicle-stimulating hormone secretion during testicular recrudescence in the male golden hamster

In the present study, to clarify whether inhibin affects follicle-stimulating hormone (FSH) secretion in the recrudescence of the male golden hamster, we used a recently developed specific enzyme-linked immunosorbent assay (ELISA) in order to measure 2 forms of inhibin molecules: inhibin B and inhibin pro-alphaC. In addition, we used the radioimmunoassay (RIA) to measure immunoreactive (ir-)inhibin, FSH, luteinizing hormone (LH), and testosterone. And finally, we used the proliferating cell nuclear antigen (PCNA) and computer-assisted sperm motion analysis (CASA) methods to ascertain how well spermatogenesis and sperm motility recover from the photoinhibition caused by exposure to a short-day (SD; 10-hour light: 14-hour dark) photoperiod. Animals were exposed to SD for 15 weeks, and then their testes were checked carefully and found to be completely regressed. Thereafter, those animals were transported to a long-day (LD; 14-hour light: 10-hour dark) photoperiod. Sampling was carried out at weeks 0 (exposed SD 15 weeks), 1, 2, 4, 6, 8, and 10. Plasma FSH rapidly increased and reached peak levels 2 weeks after transferral to the LD photoperiod and then declined to normal LD levels at week 6. Circulating ir-inhibin, inhibin B, and inhibin pro-alphaC rose to normal LD levels by week 4. A highly significant inverse correlation was observed between plasma FSH and inhibin B but not between FSH and either ir-inhibin or inhibin pro-alphaC. Plasma testosterone recovered to normal LD levels within 1 week. Sperm motility parameters were low until week 2 and recovered to normal LD levels from weeks 4 to 10. PCNA-labeled cells were confined to the spermatogenic cells of the seminiferous tubules, though Leydig and Sertoli cell nuclei were never stained for PCNA during the period studied. The number of pachytene spermatocytes and the diameter of seminiferous tubules increased in a time-dependent manner after transferral from SD to LD. In conclusion, these results suggest that 1) secretion of inhibin B may be stimulated by an early rise in FSH; 2) inhibin B suppresses FSH secretion from weeks 2 to 10, after transferral to the LD photoperiod; and 3) testes recrudescence is based on the increase in the number of sperm cells instead of the increase in the number of Sertoli and Leydig cells of the male golden hamster.     

Female sexual dysfunction and hormonal status in spinal cord injured (SCI) patients

To investigate a possible correlation between sexual hormonal status and the presence of female sexual dysfunction (FSD) using the Female Sexual Function Index (FSFI) in females with spinal cord injuries (SCI), we selected 39 SCI fertile-aged women. At visit 1, we assessed the presence of FSD using the FSFI, and all individuals were submitted to a blood hormone evaluation on the third day of their menstrual cycle. The levels of serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), thyroid-stimulating hormone (TSH), cortisol, dehydroepiandrosterone sulphate (DHEA-S), androstenedione, 17[alpha]-hydroxyprogesterone; total and free testosterone, 17beta-estradiol, inhibin, sex hormone-binding globulin (SHBG), and thyroid hormones (fT3 and fT4) were checked. Progesterone was measured on the 20th to 21st day after the menstrual cycle. In patients with amenorrhea, we tested all the hormones using 1 random blood test. After a 3-month period, the tests were repeated. Overall, 23/39 (58.9%) patients continued to manifest at least one sexual dysfunction. These patients reached a median score of 19.52. All but 6 patients (15.3%) consistently showed hormonal values within the normal range. Of the 6 patients with abnormal hormonal alterations, 5 showed at least one sexual dysfunction, 2 had low levels of total testosterone, 1 had a low level of free testosterone, 1 suffered from hypothyroidism, 1 presented with low levels of cortisol, and 1 showed hypoprogesterone. There was no significant correlation between abnormal hormonal status and the presence of a specific sexual dysfunction, as assessed with the FSFI.     

Testicular endocrine function in patients with prostatic cancer receiving medical castration by long-term administration of LH-RH agonists

Six patients with advanced prostatic cancer who had been treated by long-term administration of LH-RH agonistic preparations (Buserelin or Leupron) were tested for their pituitary-testicular endocrine functions. Serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T), prolactin (PRL), estradiol (E2) and dihydrotestosterone (DHT) were measured consecutively. In all medically castrated patients, serum levels of LH, FSH, T, DHT and E2 were suppressed and particularly serum T levels were below the castration level of 1.0 ng/ml. On the other hand, serum PRL levels were unchanged after the long-term treatment with the agonists. Serum LH and FSH levels failed to respond to LH-RH stimulation after the treatment, whereas serum T responded to stimulation by human chorionic gonadotropin (hCG) to various degrees. It was remarkable that, in 4 out of 6 medically castrated patients treated up to more than 3 years, serum T response levels above 1.0 ng/ml were noted. It is suggested that testicular endocrine function to secrete T and DHT in patients under treatment with long-term LH-RH agonist administration are still preserved in response to hCG stimulation.     

Endocrine profiles and gonadotropin response to Gn-RH of men with testicular cancer

PURPOSE: To investigate the function of the hypothalamic-pituitary-testicular axis in testicular germ cell tumors, we evaluated gonadotropin responses to gonadotropin-releasing hormone (Gn-RH), semen quality, and serum levels of sex steroid hormones in patients with testicular cancer. PATIENTS AND METHODS: Basal serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), and human chorionic gonadotropin-beta (hCG-beta) were measured before and after high orchiectomy in 20 patients with germ cell tumors of the testicle (9 with seminoma and 11 with nonseminomatous tumor). Semen quality and basal serum levels of testosterone, free testosterone, and estradiol were measured before orchiectomy. The Gn-RH test was performed before orchiectomy in all patients and after orchiectomy in patients without detectable gonadotropin levels in pre-operative serum samples. Gonadotropin levels were measured at 0, 30, 60, 90, and 120 minutes after intravenous injection of 100 micrograms of luteinizing hormone-releasing hormone (LH-RH). RESULTS: Serum gonadotropin concentrations were not detectable in 6 of 8 (75%) men with hCG positive tumors or in 4 of 12 (33.3%) men with hCG negative tumors before orchiectomy. Before surgery, 10 men without detectable gonadotropin levels showed complete suppression of the LH and FSH responses to LH-RH and 10 men with detectable gonadotropin levels showed significant increases in the LH and FSH responses (p < 0.01) at 30 minutes. After surgery, the Gn-RH test was performed in 9 men without detectable gonadotropin levels prior to surgery. Seven of these 9 men exhibited significant increases in the LH and FSH responses (p < 0.01) at 30 minutes while no response to LH-RH before or after surgery was seen in 2 men with detectable serum hCG-beta. We observed a significantly lower sperm density (median 7.5 x 10(6)/ml, range 0.4 to 17.8) in men with hCG positive tumors than in men with hCG negative tumors (median 33 x 10(6)/ml, range 0 to 103) (p < 0.002). Although testosterone levels did not differ significantly in men with hCG positive tumors and men with hCG negative tumors, free testosterone levels were significantly higher in men with hCG positive tumors (median 28.4 ng/ml, range 8.5 to 39.8) compared with men with hCG negative tumors (median 18.7 ng/ml, range 4.9 to 24.1) (p < 0.002). Estradiol levels were significantly increased in men with hCG positive tumors (median 44 pg/ml, range 26 to 110) compared with men with hCG negative tumors (median 33.5 pg/ml, range 10 to 87) (p = 0.002). CONCLUSION: The present findings indicate that serum hCG producing testicular cancers are associated with a complete suppression of the gonadotropin response to Gn-RH at the pituitary level, resulting in an inhibition of LH and FSH secretion, and also that serum hCG secreted by testicular cancers may suppresses spermatogenesis and may stimulate androgen and estradiol production by the testes. Since suppressed serum gonadotoropin levels are found in men with hCG non-producing testicular cancers, other factors derived from the tumor may cause downregulation of the gonadotropin response to Gn-RH.     

17 Alpha-oestradiol and 17 beta-oestradiol do not affect basal and follicle-stimulating hormone-stimulated inhibin B secretion by highly purified rat Sertoli cells

The effects of 17 alpha-oestradiol and 17 beta-oestradiol on basal and follicle-stimulating hormone (FSH)-stimulated inhibin B secretion by rat Sertoli cells were studied. Sertoli cells were isolated and cultivated from testes of 18-day-old Wistar rats in the presence and absence of FSH and different doses of oestrogens. On day 4 of culture, secreted inhibin was measured by enzyme-linked immunosorbent assay. Neither 17 alpha-oestradiol nor 17 beta-oestradiol had any effect on the secreted inhibin level in either the presence or absence of FSH. It is concluded that these oestradiols do not play an essential role in regulatory processes involving inhibin or FSH.