GONADOTROPHIN SUPPRESSION BY STEROIDS IN NORMAL, ADULT MALE RATS

Abstract
Effects of s.c. administration of various doses of different steroids on serum levels of LH [luteinizing hormone] and FSH [follicle stimulating hormone] in normal, adult male rats were investigated. Each steroid was injected daily during 7 days in doses of 50, 25, 12.5 or 6.25 .mu.g/100 g body wt. Ring A 5.alpha.-reduced testosterone metabolites exerted high activity in suppressing serum LH and FSH levels. 5.alpha.-Androstane-3.beta.,17.beta.-diol had in the doses tested had no such effects on serum gonadotropins. Serum LH concentrations in normal rats appeared more sensitive to steroid treatment than serum FSH concentrations.