Interactions Between LHRH, Sex Steroids and “Inhibin” in the Control of LH and FSH Secretion

Using anterior pituitary cells obtained from adult male rats, 17β‐estradiol stimulated both spontaneous and LHRH‐induced LH and FSH secretion. After in vivo administration, estrogens showed inhibitory or stimulatory effects on gonadotropin secretion, the effect being dose‐ and time‐dependent. Contrary to estrogens, androgens had differential effects at the anterior pituitary level: they inhibited LH but stimulated FSH secretion. These in vitro data were confirmed by in vivo experiments using anti‐androgens. Sertoli cell culture medium was found to be a potent inhibitor of spontaneous FSH secretion while no effect was detected on LH release. When the gonadotropin response to LHRH was studied, Sertoli cell culture medium was a more potent inhibitor of FSH than LH release although clear inhibition of LHRH‐induced LH release did occur.