Growth hormone-releasing factor releases ACTH from an AtT-20 mouse pituitary tumor cell line but not from normal pituitary cells.
Corticotropin-releasing factor (CRF) and both human pancreatic growth hormone-releasing factor (hp-GRF) and rat hypothalamic GRF (rh-GRF) stimulated ACTH release from neoplastic AtT-20 mouse pituitary tumor cells in a dose-dependent fashion, with CRF inducing a 10-fold increase and GRF a maximal increment of approximately one-half that of CRF. Neither rh-GRF nor hp-GRF induced ACTH release in normal anterior pituitary cells. Pretreatment with either dexamethasone or somatostatin prior to the addition of rh-GRF inhibited the increase in ACTH release. Both ovine CRF and rh-GRF stimulated adenosine 3,5-monophosphate production in AtT-20 cells. The weak but clearly discernible effect of GRF on ACTH release from AtT-20 cells may be due to an abnormality in the AtT-20 cell receptor.
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D051379:Mice; D010903:Pituitary Gland, Anterior / Q000187:drug effects* / Q000378:metabolism; D010911:Pituitary Neoplasms / Q000378:metabolism*; D011863:Radioimmunoassay; D013004:Somatostatin / Q000494:pharmacology
D013004:Somatostatin; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D013007:Growth Hormone-Releasing Hormone; D000242:Cyclic AMP