Endocrine, seminal and peripheral effects of depot medroxyprogesterone acetate and testosterone enanthate in men

Twenty-one day administration of dienogest reversibly suppresses gonadotropins and testosterone in normal men

Androgen-progestin combinations are promising male contraceptive regimens. Optimization of these regimens includes the development of new progestins with more favorable biological properties. In this context we tested the effects of the progestin dienogest (DNG) on reproductive hormones and metabolic parameters in men. After a 3-wk control period, 25 men were randomly assigned to receive daily doses of 2, 5, or 10 mg DNG or placebo and 10 mg cyproterone acetate for 21 d (n = 5 subjects/group). Subjects were followed for 2 wk after cessation of hormone administration. Weekly blood samples, physical examinations, hormone and chemistry measurements, semen analysis, and sexual/behavioral assessments were performed. These parameters were compared among study groups and within each group at different time points throughout the study periods. DNG and cyproterone acetate administration resulted in profound suppression of gonadotropins and T with no change in SHBG levels. No adverse effects were detected in any subject. Hormone levels returned to baseline after stopping hormone intake. DNG is a potent suppressor of gonadotropins and T in men and does not induce adverse effects over a 21-d administration. DNG is a promising progestin to be used in clinical trials for male contraception.

Potential of norethisterone enanthate for male contraception: pharmacokinetics and suppression of pituitary and gonadal function

OBJECTIVE

Gestagens are known to suppress gonadotrophins in women and are currently also under investigation for the development of hormonal male contraceptives. The aim of the study was to assess the potential of norethisterone enanthate (NETE) for male contraception.

DESIGN AND MEASUREMENTS

The suppressive effect of a single injection of 200 mg NETE on serum gonadotrophins, serum testosterone, lipids, spermatogenesis, well-being and sexual function was evaluated in seven healthy men.

RESULTS

In this single dose study treatment was well tolerated by all volunteers. NETE led to a rapid, profound and significant suppression of serum LH (day 6 - day 10), FSH (day 2 - day 29), testosterone (day 1 - day 29 and day 35) and SHBG (day 6 - day 35). At study end sperm counts were significantly suppressed. Numbers of spontaneous erections (day 17, 23 and 26), number of sexual fantasies (day 20 and 23) as well as libido (day 20 and 26) were significantly decreased compared to baseline. All other parameters including lipids, augmented glucose, testicular volume and well-being showed no significant alterations.

CONCLUSION

Because of its strong, rapid and sustained suppression of serum FSH and testosterone norethisterone enanthate offers great potential for hormonal male contraception if combined with testosterone esters.

Fluctuating trade-offs favour precocial maturity in male Soay sheep

Although trade-offs between reproductive effort and survival are commonly proposed, empirical studies that quantify the true costs and benefits of breeding activity are rare. This information is crucial, however, for examining the adaptive value of important life history traits such as age at maturity. Here we estimate both the survival cost, and genetic benefits, of precocial male maturity in a highly polygynous naturally limited population of Soay sheep. While we demonstrate that early reproduction does indeed carry a survival cost, we find that young males also achieve unexpectedly high reproductive success and that precocial mating is favoured due to the fluctuating demographic structure of the population.

Effect of testosterone enanthate on serum lipoproteins in man

Sixty-three normal Caucasian men were administered intramuscular testosterone enanthate (TE) 200 mg i.m. weekly for 12 months as part of a male contraceptive trial. This dose of TE caused a 2.5-fold increase in trough serum testosterone concentrations. High density lipoprotein cholesterol (HDL-C) was significantly depressed from pretreatment concentration of 1.19 +/- 0.04 nmol/l to 1.03 +/- 0.04 mmol/l after 12 weeks of treatment, and remained suppressed for the duration of treatment (p < 0.001). There were no changes in serum concentration of total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) or triglycerides (TG) during treatment, but the concentrations of TC and LDL-C were depressed at three months post-treatment. There was a sustained elevation in LDL-C:HDL-C ratio during TE treatment (p < 0.005), from 3.41 +/- 0.15 pretreatment to 3.88 +/- 0.19 after 12 weeks of TE treatment. Sex hormone binding globulin (SHBG), but not testosterone (T) or estradiol (E2), was significantly associated with HDL-C (r = 0.83, p = 0.001). Lipoprotein (a) (Lp(a)) was measured in a subgroup of 33 men: serum concentration fell from 187 +/- 45 mg/l pretreatment to 140 +/- 35 mg/l after 16 weeks of TE treatment (p < 0.01).

Developments in the control of testicular function

Clinicians and clinical investigators have developed improved means for controlling testicular function in men. New and refined approaches for stimulation and inhibition of the hypothalamic-pituitary-testicular axis are now available. This chapter reviewed the most successful ways to inhibit the reproductive axis in men and its current application to the treatment of precocious puberty, metastatic prostate cancer, benign prostate hyperplasia and as prospective male contraceptives. Safe, effective and reversible medical approaches to male contraception are now approaching reality. Azoospermia and severe oligozoo/azoospermia can now be accomplished in the majority of men with combined GnRH antagonists and replacement doses of testosterone. Androgens and androgen-progestogen concentrations will induce azoospermia in over 90% of Asian men and azoospermia or severe oligospermia in Caucasian ethnic groups. Field trials are ongoing to determine whether testosterone administration will be more effective than condoms as contraceptives. True precocious puberty can now be managed more effectively than in the past by suppression of gonadotropin secretion with GnRH analogues. Precocious puberty due to other causes can be treated more effectively with inhibitors of steroidogenesis and blockers of androgen action. Metastatic prostate cancer, previously treatable with either castration or oestrogens, is now amenable to suppression of androgen secretion. GnRH analogues are given either alone or combined with blockers of androgen action. While significant palliative effects are observed with endocrine ablative therapy in most men with Stage C or D prostate cancer, modest increases in duration of survival may be seen. Benign prostate hyperplasia was previously approachable only with surgical intervention. Recent data have suggested that medical treatment with 5 alpha-reductase inhibitors and/or selective alpha-adrenergic blockers may offer non-surgical alternatives in some patients. More data are needed to determine the role of medical management of this common disorder.

Reversible azoospermia induced by an androgen-progestin combination regimen in Indonesian men

The suppression of spermatogenesis by a combination of depot medroxyprogesterone acetate (DMPA) and testosterone enanthate (TE) was studied in Indonesian men. Twenty healthy, fertile volunteers were allocated randomly to either of two treatments each consisting of four intramuscular injections at monthly intervals. Group I (n = 10 men) received 100 mg DMPA plus 100 mg TE monthly while group II (n = 10 men) received 200 mg DMPA plus 250 mg TE monthly. Sperm concentration was suppressed markedly, with all men attaining azoospermia between the third and fourth month after the start of treatment. There was no significant difference in the suppression of spermatogenesis between the two dosage regimens. The median time to reaching azoospermia was 2.5 months from the onset of injections and the median time to recovery of sperm in the ejaculate was 2.0 months after cessation of treatment. Both steroid regimens were equally effective in suppressing LH, FSH and testosterone levels. Testosterone levels returned to baseline by the fourth post-treatment month while LH and FSH demonstrated significant rebound above baseline levels from 3 to 5 months after cessation of treatment. No serious clinical side effects were observed. Weight gain and increases in libido were reported during treatment by most volunteers. A transient decrease in libido was noted in 5/20 (25%) men between 1-2 months after cessation of injections, presumably due to the prolonged effects of DMPA relative to TE. These results indicate that uniform induction of reversible azoospermia with minimal side effects can be achieved in a non-Caucasian population.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of depot medroxyprogesterone acetate and testosterone oenanthate on serum lipoproteins in man

Ten normal men were given three monthly intramuscular injections of 200mg of depot medroxyprogesterone acetate (DMPA) and 250mg of testosterone oenanthate (TE) as part of a male contraceptive trial. During the three months of treatment, serum high density lipoprotein cholesterol (HDL-C) and the HDL-C:LDL-C (low density lipoprotein cholesterol) ratio were significantly depressed compared to baseline. Although the long-term effect of this alteration in lipoprotein cholesterol metabolism in normolipidaemic men is currently uncertain, these results suggest that the potential cardiovascular risks of progestagen-containing regimens for male contraception will have to be seriously considered.

Combination of 19-nortestosterone-hexyloxyphenylpropionate (Anadur) and depot-medroxyprogesterone-acetate (Clinovir) for male contraception

Because monotherapy with 19-nortestosterone hexyloxyphenylpropionate (Anadur, Pharmacia Arzneimittel, Ratingen, Federal Republic of Germany) suggested improved results for male contraception compared with available testosterone esters, it was tested for induction of complete azoospermia when combined with depot-medroxyprogesterone acetate (DMPA, Clinovir, Upjohn GmbH, Heppenheim, Federal Republic of Germany). Twelve men were treated for 7 weeks with weekly intramuscular (IM) injections of 200 mg Anadur followed by 3-weekly IM injections of Anadur up to week 15. Clinovir (250 mg) IM was administered at the start of treatment and during weeks 6 and 12. Anadur and Clinovir suppressed serum gonadotropins. Although serum testosterone declined steeply, in general, libido and potency were not impaired. Sperm concentrations were reduced significantly after 3 weeks of treatment. Lowest sperm counts were seen during week 8 of follow-up, when only 2 volunteers showed measurable sperm counts of 2.1 and 3.0 X 10(6)/ml, with a declining tendency. After 43 weeks, sperm concentrations were still below pretreatment range in 2 men, but later returned to pretreatment values. Computerized sperm motion analysis revealed that motility parameters in the residual sperm were reduced. In vitro analysis excluded a direct effect of medroxyprogesterone acetate in seminal plasma on sperm motion. The data indicate that the combination of Anadur with Clinovir increases the rate of azoospermia in normal volunteers seen under Anadur monotherapy, although the goal of azoospermia in all participants was not quite achieved.