Effects of sex steroid hormones on rat anterior pituitary LH-RH receptor.

In order to elucidate the mechanism of estrogen action at the anterior pituitary level, the effects of estradiol on the number of binding sites of LH-RH receptor in the anterior pituitary as well as its effects on the anterior pituitary responsiveness to LH-RH were studied in castrated adult female rats. Daily sc injections of 20 micrograms of 17 beta-estradiol for 2 and 4 days increased both LH-RH receptor levels and the responsiveness of the pituitary to LH-RH. This result indicates that estrogen modulates the sensitivity of the anterior pituitary to LH-RH by changing its LH-RH receptor.