Cytoplasmic progesterone receptors in the hypothalamus-preoptic area of the mouse: Effect of estrogen priming

• Published in: Journal of steroid biochemistry Vol. 19; no. 5; pp. 1571 - 1575
• Main Authors: Roselli, Charles E., Snipes, Charles A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.01.1983; New York, NY Pergamon
• Subjects: Animals; Binding, Competitive; Biological and medical sciences; Cytosol - metabolism; Estradiol - pharmacology; Female; Fundamental and applied biological sciences. Psychology; Hypothalamus - metabolism; Kinetics; Mammalian female genital system; Mice; Morphology. Physiology; Norpregnadienes - metabolism; Preoptic Area - metabolism; Promegestone - metabolism; Receptors, Progesterone - drug effects; Receptors, Progesterone - metabolism; Vertebrates: reproduction; B; progesterone; EDTA; K d; Tris; 5α-dihydroprogesterone (5α-DHP); 3α-ol; RBA; TED buffer; cortisol; B 0; B s; R5020; HPOA; Priming effect; Rodentia; Hypothalamus; Vertebrata; Mammalia; Synthetic product; Mouse; Estrogenization; Preoptic nucleus; Progesterone; Sex steroid hormone; Cytoplasm; Hormonal receptor
• ISSN: 0022-4731
• DOI: 10.1016/0022-4731(83)90372-2

A synthetic progestin, R5020, was used to identify cytoplasmic progestin receptors in the hypothalamuspreoptic area (HPOA) of ovariectomized mice. These high-affinity receptors exhibited an apparent dissociation constant of approx. 1 nM. The receptors were specific for progestins. [ 3H]R5020 binding was inhibited by more than 50% with a 50-fold excess of either radioinert R5020 or progesterone. 5α-Dihydroprogesterone inhibited binding to a lesser extent. 3α-Hydroxy-5α-pregnane 20-one and cortisol did not compete for [ 3H]R5020 binding. Administration of estradiol benzoate (10 μg), 48 h prior to death, resulted in a 54% increase in the HPOA progestin receptor concentration when compared to oil-injected controls. These data demonstrate that there are specific and saturable cytoplasmic progestin receptors in the mouse HPOA and that the concentration of these receptors is increased after estrogen treatment.