Involvement of tetrodoxin-sensitive sodium channels in rat growth hormone secretion induced by pituitary adenylate cyclase-activating polypeptide (PACAP).

摘要

Both pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38) and growth hormone-releasing hormone (GRH) stimulated growth hormone (GH) release from perfused rat anterior pituitary cells. Tetrodotoxin (TTX) blunted the GH release induced by PACAP-38 but not by GRH. Mefenamic acid, a blocker of non-selective cation channels, unaffected GH release elicited by PACAP-38 and GRH. These results suggest an involvement of TTX-sensitive Na+ channels but not Ca2+-activated nonselective cation channels in PACAP-38-induced GH secretion, and that post-receptor mechanisms for PACAP-38 are different from those activated by GRH.