OLIGOZOOSPERMIA INDUCED BY EXOGENOUS TESTOSTERONE IS ASSOCIATED WITH NORMAL FUNCTIONING RESIDUAL SPERMATOZOA

Objective: To determine the functional capacity of residual spermatozo a in semen samples from normal men with T enanthate-induced oligozoosp ermia. Design: Prospective clinical study. Setting: Academic research center. Patient(s): Twelve healthy men were studied while participatin g in a multicenter T enanthate contraceptive efficacy study. Data were analyzed from only eight subjects, whose sperm concentrations were be tween 1.3 and 10 x 10(6)/mL at the suppression phase. Intervention(s): Testosterone enanthate (200 mg) was administered LM weekly during the suppression and treatment (efficacy) phases (total 15 months). Main O utcome Measure(s): Sperm function tests (stimulated acrosome reaction, sperm hyperactivation [HA], and zona-free hamster oocyte penetration tests) were performed during the pretreatment, suppression (usually af ter 6 to 10 weeks of treatment, when sperm concentration was anticipat ed to decrease to <10 x 10(6)/mL), and recovery phases. Studies were n ot done during the contraceptive efficacy phase because only one of th e subjects was not azoospermic. Result(s): Mean sperm concentration wa s reduced but sperm motility, motility characteristics, and morphology were not affected by T enanthate treatment. The residual spermatozoa in the ejaculate could acrosome react, exhibited normal HA, and mainta ined the capacity to penetrate and fuse with the oocyte. Conclusion(s) : Suppression of spermatogenesis to moderate oligozoospermia (<10 x 10 (6)/mL) with exogenous T enanthate administration was not associated w ith impaired sperm function of the residual spermatozoa. The study did not exclude the possibility that disorders of sperm function might oc cur when spermatogenesis is suppressed further to very severe oligozoo spermia (<1 x 10(6)/mL), commonly observed in hormonal male contracept ive clinical trials. (C) 1997 by American Society for Reproductive Med icine.