After a control phase, 10 normal men received cyproterone acetate (CPA) at a dose of 25 mg/day (CPA-25; n=5) or 12.5 mg/day (CPA-12.5; n=5) plus testosterone enanthate (TE) 100 mg/week, for 16 weeks. Throughout the study sperm counts were performed every 2 weeks, and luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, biochemical and haematological tests were performed every 4 weeks. All five men in group CPA-25 and three men in group CPA-12.5 achieved azoospermia. One man in group CPA-25 was azoospermic by week 12 of hormone administration, but had a sperm count of 0.1 x 10(6)/ml at week 16. Time to azoospermia was 9.0+/-1.3 and 8.7+/-0.7 weeks in groups CPA-25 and CPA-12.5 respectively. Gonadotrophins were decreased by week 4 of hormone administration, remained around the minimum detectability of the assay for the duration of hormone administration and returned to baseline after stopping hormone administration. Testosterone values did not change. No change in any biochemical parameters was found. Haematological parameters were decreased at week 16 of hormone administration and returned to baseline after stopping hormone administration. In conclusion, these results suggest that an hormonal regimen consisting of testosterone plus a progestin with anti-androgenic properties holds promise as an effective, safe and reversible male contraceptive.
PIP: Previous research conducted by the authors demonstrated that the administration of testosterone together with high doses of the progestin cyproterone acetate (CPA) effectively suppresses spermatogenesis without adverse effects. The present study investigated the effectiveness of lower doses of CPA than those administered previously on spermatogenesis, gonadotropins, and metabolic and hematologic parameters. 10 healthy US men received CPA at a dose of 25 mg/day (CPA-25) or 12.5 mg/day (CPA-12.5) plus 100 mg of testosterone enanthate per week for 16 weeks. All 5 men who received CPA-25 and 3 of the 5 men given CPA-12.5 achieved azoospermia. The mean time to azoospermia in the two groups was 9.0 +or- 1.3 weeks and 8.7 +or- 0.7 weeks, respectively. Gonadotropins were decreased by week 4 of hormone administration, remained around the minimum of detectability of the assay for the remainder of the study period, and returned to baseline when hormone administration ceased. There was no change in testosterone values or any biochemical parameters. Hematologic parameters were decreased at week 16, but returned to baseline at the end of the study period. These findings attest that a hormonal regimen consisting of testosterone together with a progestin with anti-androgenic properties holds promise as an effective, safe, and reversible male contraceptive.