The effect of nifedipine on CRF-41 and AVP-induced ACTH release in vitro.
The effect of nifedipine on CRF-41- and AVP-induced ACTH release was examined using monolayer cultured rat anterior pituitary cells and pituitary halves. Nifedipine inhibited ACTH release induced by synthetic rat CRF-41 in two systems. In pituitary halves, CRF-41 significantly stimulated both ACTH release and cyclic AMP accumulation. Nifedipine inhibited CRF-41-induced ACTH release and the inhibitory effect of nifedipine on CRF-41-induced ACTH release was accompanied by parallel decrease of cyclic AMP levels in pituitary halves. Nifedipine did not inhibit AVP-induced ACTH release in pituitary halves, and AVP did not significantly affect cyclic AMP accumulation in pituitary halves. These results suggest that CRF-41 stimulates ACTH release through the intracellular cyclic AMP system and calcium-calmodulin system which are accelerated by the influx of extracellular calcium ions. Moreover, it is suggested that the calcium required for AVP-induced ACTH release is derived primarily from intracellular rather than extracellular sources.
Murakami
K
K
Hashimoto
K
K
Ota
Z
Z
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002478:Cells, Cultured; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D008297:Male; D009543:Nifedipine / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D001127:Arginine Vasopressin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D000242:Cyclic AMP; D009543:Nifedipine