Suppression of sperm function by depot medroxyprogesterone acetate and testosterone enanthate in steroid male contraception.

Ten normal men were given three monthly intramuscular injections of 200 mg of depot medroxyprogesterone acetate (MPA) and 250 mg of testosterone (T) enanthate. Six men became azoospermic, while four remained oligozoospermic, with a mean sperm density of 1.5 +/- 0.3 standard error of the mean million/ml. Zona-free hamster oocyte penetration was abolished in all oligozoospermic samples at the end of treatment. Twenty of the 21 oligozoospermic samples yielding at least 0.6 to 5.0 million motile spermatozoa showed a complete absence of oocyte penetration. Semen parameters returned to normal, although some took up to 12 months. These findings demonstrated an antifertility action of MPA and T enanthate on the functional capacity of residual spermatozoa and support the view that extreme oligozoospermia may be a tenable target for reversible steroid male contraception.