Antiestrogen inhibits the induction of progestin receptors by estradiol in the hypothalamus-preoptic area and pituitary.
Estradiol treatment of ovariectomized-adrenalectomized rats produced an increase in cytosol progestin binding in the hypothalamus-preoptic area (HPOA), pituitary, and uterus. In the HPOA and pituitary, this induction of progestin receptors by estradiol was inhibited by the antiestrogen CI-628 under a variety of dose and time conditions. In the uterus, inhibition of the full effect of estradiol on progestin binding was observed after 3 days of injection of antiestrogen and estradiol. In the absence of estradiol, the antiestrogen produced a slight induction of progestin receptors in the HPOA and pituitary and a substantial induction of progestin receptors in the uterus. The results suggest that the induction of progestin receptors could be a key intermediate step in some behavioral and neuroendocrine actions of estradiol.
D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D004965:Estrogen Antagonists; D005260:Female; D007031:Hypothalamus / Q000378:metabolism*; D009594:Nitromifene / Q000494:pharmacology*; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D011301:Preoptic Area / Q000187:drug effects / Q000378:metabolism*; D011372:Progestins; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D014599:Uterus / Q000187:drug effects / Q000378:metabolism
D004965:Estrogen Antagonists; D011372:Progestins; D011759:Pyrrolidines; D011956:Receptors, Cell Surface; D004958:Estradiol; D009594:Nitromifene