title: Inhibition by glucocorticoids of PGE2 and ACTH secretion induced by phorbol esters and EGF in rat pituitary cells.
abstract: In rat pituitary cells in primary culture glucocorticoids specifically inhibit PGE2 and ACTH secretions induced by TPA, a potent phorbol ester derivative (triamcinolone acetonide greater than dexamethasone greater than cortisol greater than or equal to corticosterone). However, while PGE2 secretion can be inhibited up to 80%, ACTH secretion can only be inhibited up to 40%. Similar inhibitory effects are observed with mepacrine, an inhibitor of phospholipase A2 (PLA2). Glucocorticoids having also been described as PLA2-inhibitors, their inhibitory effect on TPA-induced secretions could thus be related to their anti-PLA2 activity. Their inhibitory effect on PLA2 has been attributed to their ability to induce the synthesis of lipocortin, the activity of which could be regulated by activation of kinase C or EGF-receptor kinase. Since in our model, EGF-induced PGE2 secretion is also inhibited by dexamethasone, these results suggest that a lipocortin-like protein could be present in pituitary cells and involved in the effect of TPA and EGF on PGE2, and, at least partly, on ACTH release.
authors.affiliation: Centre de Recherches Roussel-Uclaf, Romainville, France.
authors.forename: E
authors.initials: E
authors.lastname: Dartois
authors.forename: M M
authors.initials: MM
authors.lastname: Bouton
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D002273:Carcinogens / Q000494:pharmacology; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D015232:Dinoprostone; D005938:Glucocorticoids / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D010703:Phorbol Esters / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011458:Prostaglandins E / Q000378:metabolism*; D011796:Quinacrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014222:Triamcinolone Acetonide / Q000494:pharmacology
chemical_list: D002273:Carcinogens; D005938:Glucocorticoids; D010703:Phorbol Esters; D011458:Prostaglandins E; C008876:phorbol-12,13-didecanoate; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D014222:Triamcinolone Acetonide; D011796:Quinacrine; D015232:Dinoprostone; D013755:Tetradecanoylphorbol Acetate