Search for a substance which selectively inhibits FSH--effects of steroids and prostaglandins on serum FSH and LH levels

In an attempt to find a preferential inhibitor of serum FSH, a number of C₁₈, C₁₉ and C₂₁ steroids were evaluated for suppressive effects on LH and FSH and stimulatory effects upon ventral prostate weight in the acutely castrate adult male rat. C₂₁ steroids had no effect. The C₁₉ steroids were listed in order of potency with regard to suppressing LH, FSH and stimulating ventral prostate weight. All C₁₉ steroids that had an inhibitory effect on gonadotropins also stimulated ventral prostate weight and all demonstrated preferential inhibition of LH over FSH. Two C₁₈ steroids were tested, estradiol-17β and estrone; estradiol-17β suppressed LH and FSH in a parallel fashion. Four prostaglandins were evaluated with regard to effect on gonadotropins and ventral prostate weight; none demonstrated effect.