Interaction between phosphoinositide turnover system and cyclic AMP pathway for the secretion of pancreastatin and somatostatin from QGP-1N cells.
It is found that secretion of pancreastatin and somatostatin from QGP-1N cells is regulated through muscarinic receptor-mediated activation of phosphatidylinositide hydrolysis system. In this report, whether the cAMP pathway interacts with the phosphoinositide turnover system for the secretion of pancreastatin and somatostatin from QGP-1N cells through muscarinic receptors was studied. Stimulation of QGP-1N cells with carbachol increased intracellular cAMP levels. The carbachol-induced increase in cAMP levels was inhibited by atropine. Calcium ionophore (A23187) and phorbol 12-myristate 13-acetate increased cAMP synthesis. Dibutyryl cAMP, forskolin and theophylline stimulated secretion of pancreastatin and somatostatin. When either dibutyryl cAMP, forskolin or theophylline was added in culture medium with A23187, phorbol ester or carbachol, a synergistic effect was found on pancreastatin and somatostatin secretion. These results suggest that interaction between the phosphoinositide turnover system and the cAMP pathway occurs in QGP-1N cells through muscarinic receptor stimulation for the secretion of pancreastatin and somatostatin.
First Department of Biochemistry, School of Medicine, Fukuoka University, Japan.
K
K
Tateishi
A
A
Funakoshi
N
N
Kitayama
Y
Y
Matsuoka
D007516:Adenoma, Islet Cell; D001285:Atropine / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology*; D002217:Carbachol / Q000494:pharmacology*; D002460:Cell Line; D053379:Chromogranin A; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D004357:Drug Synergism; D006801:Humans; D007700:Kinetics; D010187:Pancreatic Hormones / Q000494:pharmacology*; D010190:Pancreatic Neoplasms; D010716:Phosphatidylinositols / Q000378:metabolism*; D013004:Somatostatin / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D053379:Chromogranin A; D010187:Pancreatic Hormones; D010716:Phosphatidylinositols; C050836:pancreastatin; D005576:Colforsin; D000001:Calcimycin; D013004:Somatostatin; D003994:Bucladesine; D001285:Atropine; D002217:Carbachol; D013806:Theophylline; D000242:Cyclic AMP; D013755:Tetradecanoylphorbol Acetate