Effects of STS-557 and 20 Aet-1 on sperm functions and serum level of testosterone in bonnet monkey (Macaca radiata)

Abstract

Treatment of adult male bonnet monkeys with STS-557 (17∝-cyanomethy 1 17β-hydroxy estra-4,9(10)-dien-3-one; 12 mg/ monkey daily for 15 weeks; i.m.) reduced the sperm count from the 9th week, leading close to azoospermia on the 2nd post-treatment week which persisted until the 10th post-treatment week and normalcy was restored on the 13th post-treatment week. The sperm motility was reduced from the 9th week of treatment to 8th post-treatment week. The fertilizing ability of spermatozoa (formation of swollen sperm head or pronuclei in zona-free hamster eggs) was abolished from the 8th week of treatment to the 7th post-treatment week. The serum level of testosterone was reduced from the 2nd to 12th week of treatment (data on subsequent weeks were not collected). When 20 Aet-1 (testosterone-trans-4-n butyl cyclohexyl carboxylate; 40 mg/monkey, single; i.m.) was administered on the first day of STS-557 treatment, the sperm count was reduced from the 10th week, with near azoospermia ensuing on the 13th week which continued until the 8th post-treatment week; recovery was observed on the 12th post-treatment week. The motility was low from the 8th week of treatment to 6th week after withdrawal of treatment. The fertilizing ability of spermatozoa was abolished from the 8th week to the 12th week of treatment (data on last week of treatment were not collected). The serum level of testosterone was maintained within normal range except on the 2nd, 6th and 12th week of treatment. 20 Aet-1 alone had no significant effect on these parameters. STS-557 in combination with 20 Aet-1 may have the potentiality to be used as contraceptive for men.