SUPPRESSION OF LUTEINIZING HORMONE RELEASE BY 5α-ANDROSTANE-3α,17β-DIOL AND ITS 3β EPIMER IN IMMATURE OVARIECTOMIZED RATS

Abstract

SUMMARY: The effect of 5α-androstane-3α,17β-diol, its 3β epimer and oestradiol benzoate on suppression of LH release after ovariectomy was studied in immature rats. At doses of 50 and 100 μg/100 g body weight/day the 3α compound suppressed LH release after ovariectomy to the same extent as 0·1 μg oestradiol benzoate/100 g/day. 3α-Androstanediol at a dose of 25 μg/100 g/day suppressed LH release only up to day 45 of life, while the same dose of the 3β epimer had no effect on LH suppression. The effect of 3β-androstanediol on inducing precocious vaginal opening was found to be mediated by the ovaries, since it was eliminated by ovariectomy. These results confirm our previous findings on the participation of androstanediol in the normal regulation of LH and in the mechanism of onset of puberty in the rat.