title: Suppression of human chorionic gonadotropin by progestational steroids.
abstract: The dynamics of the secretion of human chorionic gonadotropin (hCG) were studied by culturing explants of normal term placentas for as long as 144 hours. A significant accumulation of immunoreactive hCG (beta-subunit) was first detected at 48 to 72 hours, and a sixfold increase in hCG was observed in control culture medium at 144 hours. Compared to control cultures, progesterone (P < 0.001) in physiologic tissue levels of 5 to 20 micrograms/ml, pregnenolone (P < 0.001), 20 micrograms/ml, and 20 alpha-dihydroprogesterone (P < 0.001), 20 micrograms/ml, suppressed the secretion of hCG throughout the study period. Progesterone decreased the secretion of hCG in a dose-response manner (r = -0.8S87, P < 0.1). No suppression of hCG was observed in the presence of cortisol, testosterone, dihydrotestosterone, 17 beta-estradiol, or estriol. The secretion of human chorionic somatomammotropin was unchanged in the presence of progesterone. The augmented hCG response in the presence of dibutyl cAMP (P < 0.001) was significantly, but not completely, suppressed by progesterone 20 micrograms/ml culture medium (P < 0.01). Under these conditions progestational steroids or their immediate metabolites suppress the secretion of hCG, and they may be responsible for the decline in the levels of hCG during pregnancy.
mesh_terms: D000616:Aminoglutethimide / Q000494:pharmacology; D000728:Androgens / Q000494:pharmacology; D000732:Androstanols / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology; D006063:Chorionic Gonadotropin / Q000096:biosynthesis*; D013196:Dihydrotestosterone / Q000031:analogs & derivatives*; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D009570:Nitriles / Q000494:pharmacology; D009924:Organ Culture Techniques; D010920:Placenta / Q000187:drug effects*; D011247:Pregnancy; D011372:Progestins / Q000494:pharmacology*; D011863:Radioimmunoassay
chemical_list: D000728:Androgens; D000732:Androstanols; D006063:Chorionic Gonadotropin; D004967:Estrogens; D009570:Nitriles; D011372:Progestins; D013196:Dihydrotestosterone; D000616:Aminoglutethimide; D003994:Bucladesine; C009954:trilostane; D006854:Hydrocortisone