Comparison between testosterone oenanthate-induced azoospermia and oligozoospermia in a male contraceptive study. IV. Suppression of endogenous testicular and adrenal androgens

Administration of supraphysiological doses of testosterone to normal mencauses inhibition of spermatogenesis, but while most become azoospermic,30-55% maintain a low rate of spermatogenesis. We have investigated whetherthere are differences in endogenous androgen production, of testicular andadrenal origin, which may be related to the degree of suppression ofspermatogenesis. Thirty-three healthy Caucasian men were given weekly i.m.injections of 200 mg testosterone oenanthate (TE), 18 became azoospermic,while 15 remained oligozoospermic. Urinary excretion of epitestosterone, aspecific testicular product, was reduced to <10% of pretreatment values,with no differences between the groups. Similar results were obtained forother markers of testicular steroidogenesis. Urinary and plasma adrenalandrogens were also reduced during TE treatment: a statisticallysignificant decrease in both (P < 0.001 and P < 0.05 respectively)was seen in the azoospermic but not oligozoospermic responders. Theseresults suggest that testicular steroidogenesis is decreased to <10% bythe administration of supraphysiological doses of exogenous testosterone.Differences in the degree of ongoing steroidogenesis in the testis do notappear to account for incomplete suppression of spermatogenesis, thusdifferences in androgen metabolism may underlie this heterogeneousresponse. A small but significant reduction in secretion of adrenalandrogens was also detectable, the relevance of which is unclear.