Involvement of tetrodoxin-sensitive sodium channels in rat growth hormone secretion induced by pituitary adenylate cyclase-activating polypeptide (PACAP).
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.
Murakami
Y
Y
Department of Medicine, Shimane Medical University, Izumo, Japan.
Tanaka
J
J
Koshimura
K
K
Kato
Y
Y
D000818:Animals; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D013006:Growth Hormone / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008528:Mefenamic Acid / Q000494:pharmacology; D009479:Neuropeptides / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015222:Sodium Channels / Q000187:drug effects*; D013779:Tetrodotoxin / Q000494:pharmacology*
C495403:Adcyap1 protein, rat; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D015222:Sodium Channels; D008528:Mefenamic Acid; D013779:Tetrodotoxin; D013006:Growth Hormone; D004121:Dimethyl Sulfoxide