Hormone responses to clomiphene citrate in young chimpanzees.

The responses of gonadotropin and gonadal steroids to the administration of clomiphene citrate were studied in male and female chimpanzees, aged 3.6 to 9.9 years. Follicle-stimulating hormone (FSH) was significantly reduced after treatment in the prepubertal females (n = 4) and in early pubertal males (n = 2) but not in prepubertal males (n = 5). FSH was unchanged or increased in early pubertal females (n = 2) and late pubertal males (n = 2). There was no consistent response to treatment with clomiphene citrate by luteinizing hormone (LH) in either males or females, nor by 17 beta-estradiol in the females. Testosterone levels were reduced in the early pubertal males only. These results support the hypothesis that negative feedback by gonadal steroids is operative in prepubertal chimpanzees and that puberty is accompanied by a reduction in the sensitivity to such feedback.