Multiple classes of calcium channels in mouse pituitary tumor cells.
Synthetic corticotropin-releasing factor (CRF) is a potent adrenocorticotropin (ACTH) secretagogue in the mouse pituitary tumor cell strain AtT20/D16v (D16). In the absence of added calcium in the incubation medium a dose of 5 nM CRF stimulates ACTH secretion 2-fold over control values while at medium calcium concentrations greater than 1 mM the same dose of CRF elicits a 3-fold stimulation. In the presence of EGTA or of the calcium antagonists verapamil, cobalt, or lanthanum the CRF effect is abolished. Depolarizing concentrations of extracellular K+ lead to a rapid increase in cell-associated calcium, a response which is inhibited by the dihydropyridine calcium antagonist nimodipine. Although treatment with CRF does not alter the concentration of cell-associated calcium in D16 cells, ACTH secretion stimulated by both CRF and elevated medium K+ are inhibited by nimodipine in a dose-related manner. The results indicate that D16 cells possess both voltage-sensitive and CRF-activated calcium channels.
Richardson
U I
UI
D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002999:Clone Cells; D003035:Cobalt / Q000494:pharmacology; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D007473:Ion Channels / Q000187:drug effects*; D007811:Lanthanum / Q000494:pharmacology; D051379:Mice; D009539:Nicotinic Acids / Q000494:pharmacology; D009553:Nimodipine; D010911:Pituitary Neoplasms / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D014700:Verapamil / Q000494:pharmacology
D007473:Ion Channels; D009539:Nicotinic Acids; D003035:Cobalt; D004533:Egtazic Acid; D009553:Nimodipine; D007811:Lanthanum; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D014700:Verapamil; D011188:Potassium; D002118:Calcium