title: Effects of steroid hormones on the level of corticotropin messenger RNA activity in cultured mouse-pituitary-tumor cells.
abstract: Studies have been made with the mouse pituitary tumor cell line AtT-20 in culture to determine whether or not the suppression of pituitary corticotropin messenger RNA activity observed upon the administration of glucocorticoids to adrenalectomized rats is due to a direct action of these steroid hormones on the pituitary. The levels of corticotropin messenger RNA activity in AtT-20 cells treated with various steroid hormones were measured with the use of the cell-free protein-synthesizing system derived from wheat germ. The addition of dexamethasone to culture medium reduced the level of corticotropin messenger RNA activity to 30-40% of that in untreated cells. Corticosterone and cortisol exhibited a suppressive effect to a lesser extent. In contrast, nonglucocorticoids such as testosterone and 17beta-estradiol were essentially ineffective. These results indicate that at least part of the glucocorticoid action is exerted directly on the pituitary to suppress corticotropin messenger RNA activity.
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000096:biosynthesis* / Q000494:pharmacology; D002460:Cell Line; D003345:Corticosterone / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D006854:Hydrocortisone / Q000494:pharmacology; D007700:Kinetics; D010446:Peptide Fragments / Q000494:pharmacology; D010911:Pituitary Neoplasms / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism*; D013739:Testosterone / Q000494:pharmacology
chemical_list: D010446:Peptide Fragments; D012333:RNA, Messenger; D013739:Testosterone; D004958:Estradiol; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone; D006854:Hydrocortisone