Dexamethasone is a potent stimulator of growth hormone-releasing factor-induced cyclic AMP accumulation in the adenohypophysis.
The stimulatory effect of maximal concentrations of synthetic human pancreatic growth hormone (GH)-releasing factor (GRF)(1-40)NH on cyclic AMP accumulation in rat anterior pituitary cells in culture is 4.5-fold increased following a 48-h preincubation with the potent glucocorticoid dexamethasone while the sensitivity of GRF action is increased by approximately 4-fold. Dexamethasone pretreatment, on the other hand, has no effect on basal cyclic AMP levels but approximately doubles both basal and GRF-induced GH release. The present data suggest that the potent stimulatory effect of glucocorticoids on GH secretion is exerted on the adenylate cyclase system at a step preceding cyclic AMP formation.
D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism*; D003907:Dexamethasone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D003907:Dexamethasone; D013007:Growth Hormone-Releasing Hormone; D000242:Cyclic AMP