Effect of fertility regulating agents on motility and zona-free hamster egg penetration by spermatozoa of bonnet monkey.

Administration of STS-557 (17 alpha-cyanomethyl-17 beta-hydroxyestra 4,9(10)-dien-3-one; 12 mg/monkey daily) for 4 weeks either alone or in combination with 20 Aet-1 (testosterone-trans-4-n-butyl cyclohexyl carboxylate; code CDB 1781; 40 mg/monkey single administration) had no significant effect on motility and zona free hamster egg penetration by spermatozoa of bonnet monkey, but continuation of the treatment for 12 weeks reduced (in one monkey treated with STS-557) or abolished (one treated with STS-557 and two with STS-557 + 20 Aet-1) the motility as well as zona-free hamster egg penetration (by spermatozoa of all treated monkeys). Motility and the ability to penetrate zona-free hamster egg returned to normalcy after 10 weeks of withdrawal of treatments. Active immunization of monkeys with ovine FSH (4 weeks after booster) had no adverse effect on motility of spermatozoa but none of the zona-free hamster eggs was fertilized. The correlation between motility and the capacity to penetrate the zona-free hamster eggs by monkey spermatozoa varies with the treatment. Such correlation was apparent in monkeys treated with STS-557 but not in monkeys immunized with ovine FSH.