Effects of STS 557 on semen and sperm functions in bonnet monkey (Macaca radiata)--a preliminary report

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

Treatment of adult male bonnet monkeys with STS-557 (17 alpha-cyanomethyl 17 beta-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.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of STS-557 (17 alpha-cyanomethyl 17 beta-hydroxy-estra-4, 9(10)-dien-3-one) on blood hormone levels, the testis, accessory sex organs and fertility of rats

Treatment with STS-557 (17 alpha-cyanomethyl 17 beta-hydroxy-estra-4,9(10)-dien-3-one; 10 mg kg-1 daily s.c.) for 4 weeks induced atrophy of the seminiferous tubules in adult rats with a reduction in tubule diameter and in the number of round spermatids at stage VII. Elongated spermatids were not detected. Leydig cells were atrophied from the second week of treatment with a concomitant decrease in blood levels of testosterone. The blood levels of FSH and LH were reduced from the third week of treatment. The weight of the reproductive organs was reduced after STS-557 treatment. The treatment induced sterility in 50% of rats after 2 weeks of treatment but after 4 weeks none of the treated males mated. Normal fertility and normal levels of testosterone and FSH were restored after 6 weeks and LH after 4 weeks of withdrawal of treatment. All other parameters studied recovered to pretreatment levels 6 weeks after withdrawal of treatment. STS-557 could act on the pituitary-gonadal axis (reducing gonadotrophin secretion) as well as directly affecting the Leydig cells. The consequent reduction in the blood levels of testosterone in combination with reduced gonadotrophins was presumably responsible for the suppression of spermatogenesis.

Contraceptive potentiality of STS-557--a feasibility study in male bonnet monkey (Macaca radiata)

STS-557 (17 alpha-cyanomethyl-17 beta-hydroxy-estra-4, 9(10)-diene-3-one) was administered (i.m.) to two groups (4 in each group) of adult male bonnet monkeys at a daily dose of 10 mg/monkey for 12 weeks (first group) and 5 mg/monkey for 14 weeks (second group). Treatment with the 10 mg dose resulted in a significant decline in the count, motility, acrosin and hyaluronidase activities and the fertilizing ability (zona-free hamster egg penetration assay) of spermatozoa by the 6th week of initiation of treatment. The circulating level of STS-557 was low after one week and increased from the 2nd week of treatment when the serum level of testosterone was significantly reduced. Complete recovery was observed by the 11th week after withdrawal of treatment. The treatment with the 5 mg dose had minor and inconsistent effect on the motility, hyaluronidase and acrosin activity, and the fertilizing ability of spermatozoa in addition to the blood level of testosterone. STS-557 may have the potentiality to be used as a chemical contraceptive in the male but compensation for the reduced level of blood testosterone may be necessary.