A physiological role of epidermal growth factor in male reproductive function.

Epidermal growth factor (EGF) stimulates the proliferation of various mammalian cells in culture, but its physiological role is not well defined. In mature male mice, large amounts of EGF are produced in the submandibular gland; it is present in the circulation at approximately 5 nanograms of EGF per milliliter of plasma. Sialoadenectomy (removal of the submandibular glands) decreased the amount of circulating EGF to an undetectable level but did not affect the circulating levels of testosterone or follicle-stimulating hormone. The number of mature sperm in the epididymis decreased by as much as 55 percent; the number of spermatids in the testis decreased by 40 to 50 percent; and the number of spermatocytes increased by about 20 percent. Administration of EGF to sialoadenectomized mice restored both the sperm content of the epididymis and the number of spermatids in the testis to normal. Thus, EGF may play a role in male reproductive function by stimulating the meiotic phase of spermatogenesis.

Relative roles of follicle-stimulating hormone and luteinizing hormone in the control of inhibin secretion in normal men.

The glycoprotein hormone inhibin is produced by the Sertoli cells of the testis under the influence of follicle-stimulating hormone (FSH) and is postulated in turn to inhibit FSH secretion. Luteinizing hormone (LH) is not recognized to have an important role in the control of inhibin secretion in any species. To determine the relative roles of FSH and LH in the control of inhibin secretion in man, we examined the effects of selective FSH and LH replacement on serum inhibin levels in normal men whose endogenous gonadotropins were suppressed by testosterone (T). After a 3-mo control period, nine men received 200 mg T enanthate i.m. weekly for 3-9 mo. During T treatment, serum LH and FSH levels were markedly suppressed and serum inhibin levels fell to 40% of control values. While continuing T, 3-5 mo of treatment with purified hFSH (n = 4) or hLH (n = 4) increased the respective serum gonadotropin level into the upper normal range and significantly increased inhibin levels back to 64 and 55% of control values, respectively. Supraphysiological LH replacement with high doses of human chorionic gonadotropin (n = 3) returned serum inhibin levels to 63% of control values. In no case did inhibin levels return fully to control levels. In conclusion, serum inhibin levels fell during gonadotropin suppression and were partially and approximately equally restored by either FSH or LH treatment. FSH presumably acts directly on the Sertoli cell to increase inhibin secretion whereas LH may act via increases in intratesticular T levels and/or other factor(s).

Protection of spermatogenesis in rats from the cytotoxic procarbazine by the depot formulation of Zoladex, a gonadotropin-releasing hormone agonist.

The hypothesis that adjuvant treatment designed to produce testicular atrophy would preserve fertility in males receiving cancer chemotherapy was examined in the rat. Testicular atrophy was induced by a depot formulation of Zoladex [D-Ser(Bu(t))6-Aza-Gly10-GnRH], a gonadotropin-releasing hormone (GnRH) analogue. The experiments were conducted in albino Wistar as well as in the piebald variegated rat. Rats received the depot Zoladex formulation 2 weeks before and immediately prior to being treated with four weekly doses of procarbazine (200 mg/kg). Testicular function was evaluated 50 and 90 days after the last procarbazine dose. Procarbazine induced testicular atrophy concomitant with marked germinal cell aplasia in both strains of rat. In the Wistar rat adjuvant treatment with Zoladex caused slight but not significant alleviation of the testicular toxicity of procarbazine. The testicular toxicity of procarbazine was more extensive in the piebald variegated rat, and 50 days after the last procarbazine treatment the testes were small, sperm were absent, and the stem cell index was close to zero. Serum luteinizing hormone (LH) concentrations were raised and testicular LH receptor binding was low in the presence of normal serum and testicular testosterone concentrations, indicating compensated Leydig cell failure. Testicular weight and sperm content, as well as LH receptor binding, were still decreased in rats which received both Zoladex and procarbazine, suggesting that the analogue offered no protection. However, the stem cell index of the seminiferous tubules in the procarbazine-Zoladex-treated rats was not significantly different from vehicle-treated rats, which suggested that recovery from the effects of procarbazine was in progress. Ninety days after the end of procarbazine treatment alone the testes of rats were still atrophied and there was little evidence of active spermatogenesis. Leydig cell failure appeared to have progressed as, in addition to the low testicular LH receptor content and raised serum LH concentration, the prostate and seminal vehicle weights were decreased. The combination of Zoladex treatment with procarbazine was successful in preserving testicular function in the piebald variegated rats as virtually all the functional and morphological parameters of both the seminiferous tubule and the Leydig cell were not significantly different from those of vehicle-treated rats. This study demonstrates for the first time that effective gonadal protection from the toxic effects of procarbazine chemotherapy can be achieved by administration of the depot formulation of the gonadotropin-releasing hormone analogue Zoladex. The results show clearly that complete suppression of spermatogenesis is not a prerequisite for the successful outcome of treatments designed to protect the gonad from cytotoxic chemotherapy.

Long-term reduction in sperm count after chemotherapy with and without radiation therapy for non-Hodgkin's lymphomas.

PURPOSE: Treatment of lymphomas with combination chemotherapy with or without radiation therapy (XRT) can result in long-term or permanent azoospermia. PATIENTS AND METHODS: Semen analyses of lymphoma patients were performed before, during, and after treatment with cyclophosphamide, doxorubicin, vincristine, prednisone, and bleomycin (CHOP-Bleo) chemotherapy. Some of the patients also received other drugs or radiation therapy. RESULTS: Although no patients were azoospermic before treatment, all were rendered azoospermic during treatment. Following the completion of treatment, the fraction of patients whose sperm counts recovered increased gradually over 5 years and plateaued by 7 years, with two thirds of the men achieving normospermic levels. Scattered gonadal radiation dose and cumulative cyclophosphamide dose were found to be independently significant determinants of recovery: the fraction of patients whose sperm counts recovered to 10 x 10(6)/mL were 83%, 47%, and 20% for those who received less than 9.5 g/m2 of cyclophosphamide, greater than 9.5 g/m2 of cyclophosphamide, and pelvic XRT, respectively. The inclusion of additional drugs and interferon alfa did not significantly affect the long-term recovery of spermatogenesis. CONCLUSION: Pelvic XRT and cumulative cyclophosphamide dosages greater than 9.5 g/m2 are associated with a high risk of permanent sterility in lymphoma patients treated with the CHOP-Bleo regimen.

Fertility after chemotherapy for testicular germ cell cancers.

PURPOSE: To analyze the probability of recovery of spermatogenesis after orchidectomy and cisplatin-based chemotherapy (CT) for testicular germ cell cancer. PATIENTS AND METHODS: One hundred seventy-eight patients treated between 1979 and 1991 were selected by the requirement of sperm count both pre-CT and post-CT. Counts were classified as normospermic (NS) if more than 10 x 10(6)/mL, oligospermic (OS) if 1 to 9 x 10(6)/mL, and azoospermic (AS) if less than 1 x 10(6)/mL. The median follow-up time after CT before sperm analysis was 30 months. RESULTS: Analysis of 170 patients whose spermatogenesis was reassessed at least 1 year after CT showed that of 89 patients whose pre-CT counts were NS, the post-CT count was NS in 64%, OS in 16%, and AS in 20%. There was clear evidence for continued recovery beyond 1 year; the probability of spermatogenesis increased to 48% by 2 years and 80% by 5 years. There was a significantly higher probability of recovery to OS and NS count levels in the 54 patients treated with carboplatin-rather than cisplatin-based therapy. There was an independent and similar effect of normal pre-CT count. There was a reduced probability to recover to OS in the 26 patients treated with more than four cycles of CT. A prognostic model identified three groups with 25%, 45%, and 82% probabilities of recovering spermatogenesis by 2 years after CT. CONCLUSION: Analysis of pre-CT sperm count together with details of planned treatment can be used to predict recovery of spermatogenesis following germ cell CT.

Male gonadal function after chemotherapy for solid tumors in childhood.

The testicular function of 30 adolescent or adult males having undergone polychemotherapy in childhood was assessed by means of a spermogram or testicular biopsy. At the time of examination, the patients were pubertal and had completed chemotherapy between 1 and 20 years previously (mean, 9 years). All patients who were prepubertal or intrapubertal at the time of treatment achieved normal puberty with normal growth. Twenty patients presented with azoospermia and/or severe disturbances in the germinal line on biopsy. This series confirms the toxicity of alkylating agents, in particular that of the mechlorethamine, vincristine, procarbazine, and prednisone combination (MOPP) and that of cyclophosphamide (CPM). However, dactinomycin, vinblastine, and vincristine did not appear to have a toxic effect on spermatogenesis. The prepubertal state did not protect the gonads of 19 patients who were prepubertal at diagnosis: 12 are now sterile as a result of the treatment. An increase in basal follicle-stimulating hormone (FSH) levels gives a good indication of testicular damage, although normal levels do not rule out the possibility of azoospermia.

Effectiveness of carboplatin, etoposide, and bleomycin combination chemotherapy in good-prognosis metastatic testicular nonseminomatous germ cell tumors.

The combination of carboplatin, etoposide, and bleomycin (CEB) was evaluated as initial chemotherapy in 76 patients with good-prognosis metastatic nonseminomatous germ cell tumors (NSGCT) between 1984 and 1988. The classification of eligible patients included Royal Marsden Hospital (RMH) stages IM, IIA, IIB, IIC, IIIA, IIIB, IV0ABCL1, and IV0ABL2. Four courses of combination chemotherapy were administered in a 21-day cycle, and surgical excision of residual mass was performed in 27 cases (23 laparotomies and four thoracotomies). At the time of analysis, median follow-up was 24 months from start of chemotherapy (range, 6 to 54 months). The 2-year cause-specific survival probability was 98.5%, the single cause-related mortality being caused by bleomycin pneumonitis. Five patients failed CEB chemotherapy, but all have been successfully salvaged with a combination of surgery and intensive chemotherapy, follow-up from completion of all treatment being 35 to 44 months. The toxicity of CEB included bone marrow suppression and alopecia in all patients but no significant neurotoxicity or ototoxicity, and minimal renal toxicity. Only four (5%) patients had a decrease in the glomerular filtration rate greater than 15%. In 51% of patients, the hemoglobin fell below 10 g/dL. The WBC count nadir was less than 1,500/microL in 11% of treatment cycles and in 16% the platelet nadir fell below 50,000/microL. Decreases in the WBC and platelet counts were of very brief duration. Only one of 310 CEB cycles was complicated by neutropenic sepsis, and there were no episodes of thrombocytopenic purpura or bleeding. We conclude that the CEB combination represents an effective alternative to cisplatin-based chemotherapy in good-prognosis NSGCT and that the replacement of cisplatin by carboplatin leads to reduced toxicity.

Gonadal function following chemotherapy for Hodgkin's disease: a comparative study of MVPP and a seven-drug hybrid regimen.

PURPOSE AND METHODS: Gonadal function was assessed in 89 patients after chemotherapy for Hodgkin's disease (HD). Thirty-seven patients had received mechlorethamine, vinblastine, prednisolone, and procarbazine (MVPP) and 52 patients, a hybrid combination of chlorambucil, vinblastine, prednisolone, procarbazine, doxorubicin, vincristine, and etoposide (ChIVPP/EVA). Fifty men (MVPP, n = 21; ChIVPP/EVA, n = 29) with a median age of 26 years (range, 16 to 54) and 39 women (MVPP, n = 16; ChIVPP/EVA, n = 23) with a median age of 30 years (range, 15 to 47) were studied at a median of 30 months (range, 4 to 83) following chemotherapy. RESULTS: Semen analysis showed azoospermia in 35 of 37 men, and increased serum follicle-stimulating hormone (FSH) levels in this group confirmed severe germinal epithelial damage. Analysis of pretreatment semen in 28 men showed azoospermia in one, oligospermia in four (sperm count < 20 x 10(6)/mL), and a normal sperm count in the remaining 23. In the women, 26 of 34 (76%) with a regular menstrual cycle before commencing chemotherapy became amenorrheic following treatment. Menses returned in 10 women, who had a median age of 25 years (range, 21 to 34), and there were two pregnancies in this group. In the other 16, with a median age of 36 years (range, 27 to 47), amenorrhea persisted and premature ovarian failure was confirmed by increased serum gonadotrophins and reduced estradiol (E2) concentrations. Of the original eight women in whom menses were maintained following treatment, two subsequently developed amenorrhea and the clinical and biochemical features of an early menopause. In total, 18 of 34 women (53%) required hormone replacement therapy for chemotherapy-induced ovarian failure. CONCLUSION: There was no statistically significant difference in the frequency or severity of gonadal dysfunction between MVPP- and ChIVPP/EVA-treated patients. We conclude that both of these chemotherapy schedules cause substantial damage to gonadal function in both sexes.

Brief chemotherapy, Stanford V, and adjuvant radiotherapy for bulky or advanced-stage Hodgkin's disease: a preliminary report.

PURPOSE: Although survival rates have improved for patients with bulky and advanced-stage Hodgkin's disease (HD), current treatments entail substantial acute morbidity and risks for late effects such as infertility, second malignancies, and cardiopulmonary toxicities. A novel, brief chemotherapy regimen (doxorubicin, vinblastine, mechlorethamine, vincristine, bleomycin, etoposide, and prednisone [Stanford V]) was designed to shorten the duration of treatment, significantly reduce cumulative doses of alkylating agents, doxorubicin, and bleomycin, and maintain dose-intensity (DI). This brief chemotherapy was combined with radiation therapy (RT) to bulky disease sites. METHODS: Since May 1989, 65 previously untreated patients were treated for stage II HD with bulky mediastinal involvement (n = 21) or for stage III or IV HD (n = 44). Patients received weekly chemotherapy for 12 weeks. Consolidative RT was given to the first 25 patients to sites of initial bulky disease or radiographic abnormalities that persisted after chemotherapy; in the remaining 40 patients, RT was limited to bulky disease (adenopathy > or = 5 cm and/or macroscopic splenic nodules defined by computed tomography [CT]). RESULTS: With a median follow-up period of 2 years, actuarial 3-year survival rate is 96% and failure-free survival (FFS) rate is 87%. The 3-year FFS rate is 100% for stage II patients with bulky mediastinal disease and 82% for patients with stage III to IV disease. There were no treatment-related deaths. In a preliminary analysis on a subset of patients, female and male fertility appears to be preserved. CONCLUSION: These preliminary results indicate that the Stanford V chemotherapy regimen with or without RT is well-tolerated and effective therapy for bulky, limited-stage, and advanced-stage HD. Less cumulative exposure to alkylating agents, doxorubicin, and bleomycin and limited use of radiation is expected to decrease risks for second neoplasms and late cardiopulmonary toxicity. Based on these results, the Stanford V chemotherapy with or without RT regimen deserves further study in the context of a randomized clinical trial.

Evaluation of reproductive capacity in germ cell tumor patients following treatment with cisplatin, etoposide, and bleomycin.

PURPOSE: To evaluate the infertility rate in patients with germ cell tumors receiving chemotherapy with cisplatin, etoposide (VP-16), and bleomycin (PVP16B). PATIENTS AND METHODS: Thirty patients were evaluated. All patients had undergone chemotherapy with two to four cycles of PVP16B. A single semen analysis was performed 24 to 78 months following initiation of chemotherapy. All 30 patients were continuously disease-free. Eight of these patients had also undergone nerve-sparing retroperitoneal lymph node dissection (RPLND). RESULTS: The median sperm concentration was 33.9 x 10(6), with a median volume of 3.2 mL. The median total sperm count was 86.4 x 10(6). Oligospermia (< 40 x 10(6) total sperm count) was found in 13 patients (43%), including six (20%) who were azoospermic. There was a high incidence of morphologically abnormal sperm, with only one patient having more than 50% normal spermatozoa. Only 13 patients (43%) had sperm motility greater than 50%. Five patients had positive semen antisperm immunoglobulin G (IgG). Eight patients fathered children, including three with document oligospermia. CONCLUSION: Patients with germ cell tumors successfully treated with PVP16B chemotherapy are at substantial risk for persistent semen abnormalities. However, some patients with oligospermia will slowly recover and others are still capable of reproductive capacity despite continued oligospermia.

Long-term fertility and Leydig cell function in patients treated for germ cell cancer with cisplatin, vinblastine, and bleomycin versus surveillance.

Fertility and Leydig cell function were investigated in 31 patients previously treated for nonseminomatous testicular cancer. Twenty-two patients with metastatic cancer had received cisplatin-based chemotherapy, and the median follow-up was 64 months (range, 42 to 100 months). Nine patients without metastases were treated with orchiectomy alone, and follow-up in this group was a median of 61 months (range, 40 to 77 months). None of the patients have relapsed and retroperitoneal lymph node dissection was not performed in any patient. Both the concentration of spermatozoa and the volume of the remaining testis are significantly reduced in patients who had previously received chemotherapy when compared with patients treated with orchiectomy alone (P less than .05). There were no significant differences between groups when comparing morphology, motility, and penetration of the spermatozoa. Subclinical Leydig cell dysfunction with normal testosterone and elevated luteinizing hormone (LH) was observed in one patient (11%) treated with orchiectomy alone, while 59% of the patients who had received chemotherapy had elevated LH (P less than .05). We conclude that cisplatin-based chemotherapy leads to a persistent impairment of fertility and Leydig cell function in the majority of patients with testicular cancer.

Involvement of epidermal growth factor deficiency in pathogenesis of oligozoospermia in streptozotocin-induced diabetic mice.

Based on previous findings that epidermal growth factor (EGF), which plays an important role in maintenance of spermatogenesis, is deficient in diabetic mice, the significance of EGF deficiency in the pathogenesis of oligozoospermia in streptozotocin-induced diabetic mice was studied. EGF levels in the submandibular glands and plasma of diabetic mice were 0.61 +/- 0.07 micrograms/mg tissue and 0.25 +/- 0.02 ng/ml (mean +/- SE), respectively, whereas those of normal mice were 1.63 +/- 0.08 micrograms/mg tissue and 0.54 +/- 0.04 ng/ml, respectively. The epididymal sperm counts of diabetic mice, 4.7 +/- 0.14 x 10(5)/mg tissue, were significantly lower (P less than 0.01) than those of normal mice, 6.0 +/- 0.10 x 10(5)/mg tissue. Administration of EGF (5 micrograms/mouse/day) to diabetic mice significantly (P less than 0.01) increased their sperm counts to 5.5 +/- 0.16 x 10(5)/mg tissue without affecting plasma levels of testosterone and glucose. Furthermore, insulin treatment (1 U/mouse/day) of diabetic mice restored the submandibular gland, plasma EGF concentrations, and sperm counts to normal levels. The restorative effects of insulin on sperm production appeared to be mediated, at least in part, by EGF, because its effect was significantly (P less than 0.01) reduced by the concomitant administration of EGF antiserum. In addition, the plasma testosterone levels of diabetic mice, 67 +/- 14.3 ng/ml, were lower that those of normal mice, 122 +/- 19.1 ng/ml. Administration of testosterone (1 mg/mouse/day) normalized the submandibular gland and plasma EGF levels and significantly increased sperm counts in the epididymis. These results suggest that EGF deficiency is a possible cause for the pathogenesis of oligozoospermia in diabetic mice.

Temporal and stage-specific changes in spermatogenesis of rat after gonadotropin deprivation by a potent gonadotropin-releasing hormone antagonist treatment.

GnRH antagonists (GnRH-As) rapidly and reversibly inhibit testicular functions in a variety of experimental models as well as man. Their potential for human male contraception is currently being tested in many centers, including our own. This study was undertaken to provide comprehensive quantitative information on the testes and to document the temporal and stage-specific changes in the kinetics of germ cell degeneration in rats treated daily with the Nal-Glu GnRH-A (1250 micrograms/kg body wt) for up to 4 weeks. Plasma levels of testosterone (T) and the concentrations of testicular T declined to 20.7% and 5.4% of control values, respectively, by 1 week and remained suppressed throughout the treatment period. Preleptotene and pachytene spermatocytes, and step-7 and step-19 spermatids at stage VII were the first germ cells to degenerate soon after (1 week) GnRH-A treatment. Germ cell counts at stage VII also revealed a significant (P < 0.05) reduction in number of preleptotene (25.6%), pachytene (35.4%), and step-7 spermatids (29.1%) in comparison with controls. The number of homogenization-resistant advanced spermatids decreased by 70%. A further progressive loss of spermatogenic activity occurred with time. Treatment with GnRH-A for 4 weeks caused advanced spermatids to decline to nearly undetectable, Step-7 spermatids to decline to 17.7% of the normal level, and the P and PL to decline to 28.6% and 67.7%, respectively, of control values. The number of Sertoli cells and A1 spermatogonia remained unchanged throughout the experimental period. The effects of GnRH-A treatment on spermatogenesis were identical to that of hypophysectomy. These results suggest that: 1) early deprivation of gonadotropins and/or intratesticular T by GnRH-A treatment is followed by stage-specific degeneration of germ cells; 2) pituitary secretions other than LH and FSH have little primary influence on spermatogenesis during early regression; and 3) the GnRH-A-treated rat would be an excellent animal model for studying the targeted effects of LH, FSH, and T on the regulation of spermatogenesis.

Suppression of human spermatogenesis by testosterone implants.

Hormonally induced azoospermia is an effective, reversible form of male contraception; however, some men treated with weekly im testosterone enanthate (TE) injections fail to become azoospermic. As weekly injections cause widely fluctuating and supraphysiological testosterone levels, we tested the hypothesis that more stable, physiological testosterone levels would consistently produce azoospermia. Using a depot testosterone formulation which provides stable, physiological range testosterone levels for up to 6 months, we studied nine men before and after insertion of six 200 mg testosterone implants under the abdominal wall skin and compared the results with 38 men treated in a previous study with weekly im injections of 200 mg TE. Testosterone implants suppressed sperm output to near-azoospermia between the second to fourth postimplant months returning to normal by the sixth postimplant month. The fall in sperm output at the first month was greater after testosterone implants than TE injections (58% vs. 17%, P = 0.011) but similar proportions of men became azoospermic (5/9 vs. 25/38) or severely oligozoospermic (< 1 million/ml; 9/9 vs. 37/38). Plasma testosterone and estradiol levels remained mostly within the eugonadal range after implants but were markedly supraphysiological during TE injections. Both treatments suppressed immunoreactive LH and FSH to undetectable levels by ultrasensitive fluoroimmunoassay. Sex hormone-binding globulin levels were decreased and PRL levels increased by TE injections but neither was changed by testosterone implants. Prostate-specific antigen demonstrated a small rise of marginal significance (P = 0.065) after testosterone implants. Fewer men experienced acne after implants (0/9 vs. 25/38, p = 0.0004). Therefore a depot testosterone preparation with quasi-zero-order release demonstrates higher dose efficiency with similar (but not uniform) efficacy at inducing azoospermia but may cause fewer androgenic side-effects than weekly TE injections.

PIP: In Sydney, Australia, researchers analyzed data on 9 healthy men aged 21-50 to determine the effects of 6 long acting depot testosterone (200 mg) implants under the abdominal wall on spermatogenesis. They also compared these data with retrospective data on 38 healthy men who had received weekly testosterone (200 mg) injections to determine whether steady-state testosterone levels within the physiological range might achieve azoospermia uniformly in fertile men. The implants dramatically decreased sperm output to near 0 levels between the 2nd and 4th month after implantation. By 6 months postimplant the sperm density had returned to normal. The injections produced similar reductions in sperm output, but the rate of decrease was significantly greater at the first month in men with the implants (58% vs. 17%; p = 0.011). Similar proportions of men in the implant group and the injection group had achieved azoospermia (56% vs. 66%) or severe oligospermia (1 million sperm/ml; 100% vs. 97%). Plasma testosterone and estradiol levels largely stayed within the eugonadal range after insertion of implants. They were considerably supraphysiological during testosterone injections, however. Both testosterone implants and testosterone injections inhibited immunoreactive luteinizing hormone and follicle stimulating hormone (p 0.05). Testosterone injections reduced sex hormone binding globulin levels but increased PRL levels (p 0.05). Testosterone implants increased prostate-specific antigen by about 20% (p = 0.065). Acne was more prevalent after injections than after implants (0/9 vs. 25/38; p = 0.0004). Both testosterone treatments had biochemical effects of similar magnitude. These findings suggest that the testosterone implants with quasi-zero-order release have a higher dose efficiency than the injections with similar efficacy at achieving azoospermia, but may result in fewer androgenic side effects than the injections.

Stereological evaluation of human spermatogenesis after suppression by testosterone treatment: heterogeneous pattern of spermatogenic impairment.

Testosterone (T) treatment suppresses gonadotropin levels in normal men and is a promising reversible contraceptive that induces azoospermia in approximately 70% of subjects and oligospermia in the remainder; however, the basis of this variable response is unclear. This study aimed to investigate this reported variable response by examining the spermatogenic process and quantitating germ cell number in men after T-induced gonadotropin withdrawal. Ten normal fertile men (31-46 yr), already planning to undergo vasectomy, either received T enanthate (200 mg, i.m., weekly) for 19-24 weeks (n = 5; TE group) or proceeded directly to surgery (n = 5; controls), at which time a unilateral testicular biopsy was taken, and germ cell numbers were estimated using the optical disector stereological method. In response to TE treatment, serum T levels rose 2-fold, and FSH/LH levels became undetectable. Sperm counts fell to azoospermia in 4 men and to 21 million/mL in the fifth man. The mean number of type A spermatogonia per 100 Sertoli cells was unchanged, but type B spermatogonia fell markedly to 10% of the control values, and later germ cell types decreased to 11-18% of the control values. The pattern of germ cell suppression varied widely and showed no relationship with sperm count or the time to azoospermia. Despite the presence of elongated spermatids (1.4-20% of the control), four men remained azoospermic. Two TE subjects with similar early germ cell complements and elongated spermatid numbers had sperm counts of zero and 21 million/mL; the latter man demonstrated marked variability in germ cell numbers between adjacent tubules. We conclude that 1) the principal spermatogenic lesion in TE-treated men is the marked (90%) inhibition of type A-->B spermatogonial maturation. Other sites are also affected, particularly the release and/or survival of elongated spermatids during transit; and 2) a steady state in germ cell number may not be established even after 4-5 months of TE treatment. The findings suggest that TE treatment does not adequately or consistently withdraw hormonal support for spermatogenesis, leading to variable between- and within-individual patterns of germ cell suppression.

Stimulation of serum inhibin concentrations by gonadotropin-releasing hormone in men with idiopathic hypogonadotropic hypogonadism.

Inhibin is a gonadal hormone thought to be important in FSH regulation. We investigated the effects of the hypogonadotropic state and subsequent GnRH-induced increases in gonadotropin levels on inhibin secretion. Serum levels of inhibin, LH, FSH, and testosterone (T) as well as sperm concentrations were measured in 5 men with idiopathic hypogonadotropic hypogonadism (IHH) before (baseline) and during 8 weeks of GnRH therapy (5 micrograms, sc, every 2 h). Baseline and peak inhibin levels were compared to those in a group of 19 normal men. Before GnRH administration, the mean serum inhibin level was significantly lower in the IHH men than in the normal men [166 +/- 56 (+/- SE) vs. 588 +/- 30 U/L; P less than 0.001]. Serum inhibin levels rose after 1 week of GnRH therapy (P less than 0.05) and remained higher than the baseline level thereafter. The mean peak inhibin level during GnRH administration was lower than the mean value in normal men (485 +/- 166 vs. 588 +/- 30 U/L; P less than 0.05). Serum LH and FSH levels rose promptly to the midnormal range or slightly above it. Serum T levels did not significantly increase until 4-5 weeks of GnRH administration and remained in the low normal range. All IHH men were azoospermic throughout the study. These data are consistent with the hypothesis that inhibin is produced by the testis under gonadotropin control. They also suggest the possibility of defective Sertoli and Leydig cell function in men with IHH, since the men's serum inhibin and T levels did not rise to the same extent as did their normalized serum gonadotropin levels during GnRH administration.

Follicle-stimulating hormone is required for quantitatively normal inhibin secretion in men.

Inhibin is a glycoprotein hormone produced by the testis and ovary which is postulated to be an important regulator of pituitary FSH secretion. Animal data indicate that inhibin is produced by the Sertoli cells of the testis under the influence of FSH. To determine the role of FSH withdrawal and replacement in the control of inhibin secretion in man, we measured serum inhibin concentrations in men in whom isolated FSH deficiency had been produced by chronic hCG administration; this was followed by FSH replacement. After a 3-month control period, four normal men received hCG for 7 months, resulting in suppression of serum FSH to undetectable levels and urinary FSH excretion to prepubertal levels. Their mean serum inhibin levels fell to 70% of control values during hCG administration [362 +/- 60 (+/- SE) vs. 518 +/- 56 U/L; P less than 0.01]. While continuing hCG, testosterone enanthate was administered for a further 6 months. Serum FSH and inhibin levels remained suppressed to a similar degree. Testosterone administration then was ceased, and hCG continued for a further 2-4 months. Then, while continuing hCG administration, FSH was replaced as either highly purified human FSH (n = 2) or human menopausal gonadotropin (n = 2) for a period of 4-10 months. Serum FSH levels increased to the mid- and upper normal male ranges, respectively. FSH replacement restored serum inhibin levels to 522 +/- 56 U/L (P = NS vs. control). In summary, prolonged selective FSH deficiency induced by chronic hCG administration suppressed inhibin secretion. Replacement of FSH activity restored inhibin secretion to control values. We conclude that 1) FSH is not absolutely required for inhibin secretion in men; and 2) the maintenance of quantitatively normal inhibin secretion requires the combined action of both gonadotropins.

Effects of chronic testosterone administration in normal men: safety and efficacy of high dosage testosterone and parallel dose-dependent suppression of luteinizing hormone, follicle-stimulating hormone, and sperm production.

In normal men, chronic testosterone (T) administration results in negative feedback suppression of gonadotropin and sperm production. However, azoospermia is achieved in only 50-70% of men treated with high dosages of T. Furthermore, the relative sensitivity of LH and FSH secretion to chronic administration of more physiological dosages of T is unclear. We determined whether a T dosage higher than those previously given would be more or less effective in suppressing spermatogenesis and whether, within the physiological range, T would exert a more selective effect on LH than on FSH secretion. After a 4- to 6-month control period, 51 normal men were randomly assigned to treatment groups (n = 9-12/group) receiving either sesame oil (1 mL) or T enanthate (25, 50, 100, or 300 mg, im) weekly for 6 months. Monthly LH and FSH levels by RIA and twice monthly sperm counts were determined. During treatment, T levels were measured daily between two weekly injections. Chronic T administration in physiological to moderately supraphysiological dosages resulted in parallel dose-dependent suppression of LH, FSH, and sperm production. T enanthate (50 mg/week) suppressed LH and FSH levels and sperm counts to 50% of those in placebo-treated men (ED50). T enanthate (300 mg/week), was no more effective than 100 mg/week in suppressing LH, FSH, and sperm production. Serum T levels in men who received 100 and 300 mg/week T enanthate were 1.5- and 3-fold higher than those in placebo-treated men, respectively. Except for mild truncal acne, weight gain, and increases in hematocrit, we detected no significant adverse health effects of chronic high dosage T administration. We conclude that 1) LH and FSH secretion are equally sensitive to the long term negative feedback effects of T administration; 2) sperm production is suppressed in parallel with the LH and FSH reductions induced by chronic T administration; and 3) even at the clearly supraphysiological dosage of 300 mg/week, T enanthate does not reliably induce azoospermia in normal men. However, there was also no evidence of a stimulatory effect of this T dosage on spermatogenesis. Furthermore, we found no evidence of major adverse health effects of T administered chronically even at the highest dosage.

PIP: In Seattle, Washington, health workers randomly assigned 51 healthy men (mean age, 29 years) to a group that was to receive either 1 ml sesame oil or testosterone enanthate (T enanthate) at various doses once a week for 6 months so an investigator could determine the safety and efficacy of long-term administration of T enanthate in suppressing spermatogenesis and whether it would bring about a more selective feedback effect on luteinizing hormone (LH) than on follicle stimulating hormone (FSH) secretion. 4-6 months prior to treatment, observations and measurements were performed with no administration of hormones. T enanthate effected a significant dose-dependent suppression of both serum LH and FSH levels. At 50 mg of T enanthate per week, the LH level was 65% and the FSH level was 62% of control values; at 100 mg/week, the levels were at 32% and 34% of control values, respectively. T enanthate also contributed to a significant dose-dependent suppression of both sperm counts and concentrations. At 50 mg/week, the sperm count was 36% of control values; at 100 mg/week, it was 0.8% of control values. T enanthate at a dose of 300 mg/week was no more effective than 100 mg/week. The dose-dependent suppression curves were parallel for the hormones, sperm counts, and sperm concentrations. Men who received 100 mg and 300 mg T enanthate per week had higher T levels than the men treated with sesame oil. These levels were at and above the upper limits of the normal range. The men suffered from no significant adverse health effects. There were cases of mild truncal acne, weight gain, and increases in hematocrit. These findings show that LH and FSH secretion are sensitive to long-term negative feedback effects of T administration as well as is spermatogenesis. T enanthate may prove to be a useful male contraceptive agent.

Comparison between testosterone enanthate-induced azoospermia and oligozoospermia in a male contraceptive study. I: Plasma luteinizing hormone, follicle stimulating hormone, testosterone, estradiol, and inhibin concentrations.

Sex-steroid based male contraceptive regimes induce azoospermia in only 40-70% of Caucasian men. The reason(s) why the remainder maintains a low level of spermatogenesis (oligozoospermia) despite gonadotrophin suppression is unclear. In order to improve our understanding of this phenomenon, we examined the changes in sperm density and plasma LH, FSH, testosterone (T), oestradiol (E2), and inhibin (IN) in 28 normal men who received 200 mg testosterone enanthate (TE) im weekly during a male contraceptive efficacy trial. Gonadotrophins were measured by an ultrasensitive time-resolved immunofluorometric assay (DELFIA) with a sensitivity of 0.04 U/L, to determine the adequacy of suppression. Seventeen of the 28 men achieved azoospermia; the other 11 remained oligozoospermic (sperm density 3.3-4.7 x 10(6)/mL) after 6 months of TE exposure. Azoospermic subjects displayed a more rapid decline in sperm density, a significant difference being apparent by 5 weeks after starting TE. During TE treatment, both LH and FSH were consistently suppressed to below the limits of detection, whereas there was a 2.5-fold rise in T and E2 with a similar decrease in IN. There were no consistent differences in any of these hormone concentrations between the azoospermic and oligozoospermic groups. Recovery of sperm density to baseline levels or above 20 x 10(6)/mL was significantly slower in the azoospermic group. During the recovery phase, the azoospermic men exhibited significantly higher LH and FSH levels compared to baseline and to the oligozoospermic subjects even though no differences in circulating T, E2, or IN were observed. We conclude that incomplete gonadotrophin suppression or differences in sex steroid or inhibin levels are unlikely to be responsible for the maintenance of minor degrees of spermatogenesis in some men during TE administration. The rebound rise in gonadotrophins in azoospermic but not oligozoospermic responders during recovery may reflect a more profound degree of spermatogenic suppression in the former group.

PIP: In the UK, 28 healthy, fertile, white 23-40 year old men received an intramuscular injection of 200 mg testosterone enanthate (TE) during a male contraceptive efficacy trial. Only 17 men achieved azoospermia. Researchers used ultrasensitive immunofluorometric assay to measure gonadotropins and took venous blood samples right before the next TE injection to measure circulating steroid and inhibit (IN) levels. They wanted to determine whether gonadotropin suppression or changes in circulating steroid and IN levels during TE administration maintain some level of spermatogenesis in the 11 oligozoospermic men. At 5 weeks after beginning TE administration, azoospermic men experienced a more rapid fall in sperm density than oligozoospermic men (18.7 x 1 million/mL vs. 48.4 x 1 million/mL; p .05). In both groups, luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels were always lower than the assay detection limit during TE administration. On the other hand, after TE administration, testosterone (T) and estradiol (E2) levels increased 2.5 times while IN levels fell 2.5 times. Azoospermic men recovered sperm density at or above 20 x 1 million/mL at a slower rate than did oligozoospermic men (p .01). They had significantly higher LH and FSH levels during the recovery phase compared to baseline levels and to those of oligozoospermic men (p .05). Yet, circulating levels of T, E2, or IN were essentially the same in both groups. These results suggest that neither incomplete suppression if pituitary gonadotropins nor differences in sex steroid or IN levels would likely account for the differences in the degree of spermatogenic suppression in the 2 groups of men receiving exogenous TE administration. The faster rise in gonadotropins in azoospermic men during recovery may intimate that they experience a more profound degree of spermatogenic suppression.

Chronic human chorionic gonadotropin administration in normal men: evidence that follicle-stimulating hormone is necessary for the maintenance of quantitatively normal spermatogenesis in man.

The role of FSH in the maintenance of spermatogenesis in man is poorly understood. To determine whether normal serum levels of FSH are necessary for the maintenance of quantitatively normal spermatogenesis, we first studied the effect on sperm production of selective FSH deficiency induced by chronic administration of hCG in normal men. Then, we determined the effect of FSH replacement in some of these men. After a 3-month control period, eight normal men (aged 30-39 yr) received 5000 IU hCG, im, twice weekly for 7 months. Then while continuing the same dosage of hCG, subjects simultaneously received 200 mg testosterone enanthate (T), im, weekly for an additional 6 months. hCG administration alone resulted in partial suppression of the mean sperm concentration from 88 +/- 24 (+/-SEM) million/ml during the control period to 22 +/- 7 million/ml during the last 4 months of hCG treatment (P less than 0.001 compared to control values). With the addition of T to hCG, sperm counts remained suppressed to the same degree. Except for one man who became azoospermic while receiving hCG plus T, sperm motilities and morphologies remained normal in all subjects throughout the entire study. During both the hCG alone and hCG plus T periods, serum FSH levels were undetectable (less than 25 ng/ml), and urinary FSH levels were comparable to those in prepubertal children and hypogonadotropic hypogonadal adults. We replaced FSH activity in four of the eight men in whom prolonged selective FSH deficiency and partial suppression of sperm production were induced by hCG administration. Immediately after the period of hCG plus T administration, T was stopped in four men who continued to receive hCG alone (5000 IU, im, twice weekly) for 3 months. Then, while continuing the same dosage of hCG, these men received 100 IU human FSH, sc, daily (n = 2) or 75 IU human menopausal gonadotropin, sc, daily (n = 2) for 5-8 months. During the second period of hCG administration alone, serum FSH levels were undetectable (less than 25 ng/ml), and sperm concentrations were suppressed (34 +/- 13 million/ml) compared to the control values for these four men (125 +/- 39 million/ml; P less than 0.001). With the addition of FSH to hCG, FSH levels increased (213 +/- 72 ng/ml) and sperm concentrations rose significantly, reaching a mean of 103 +/- 30 million/ml (P less than 0.03 compared to hCG alone).(ABSTRACT TRUNCATED AT 400 WORDS)