Phosphatidic acid production, required for cholecystokinin octapeptide-stimulated amylase secretion from pancreatic acinar AR42J cells, is regulated by a wortmannin-sensitive process.
To investigate the role of phospholipids in exocytotic secretory events, we utilized rat pancreatic acinar AR42J cells that secreted amylase in response to cholecystokinin octapeptide (CCK-8). Wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K), was found to inhibit the secretion in a dose-dependent manner. When changes in cell membrane phospholipids were investigated before and after CCK-8 stimulation using [32P]orthophosphoric acid-labeled AR42J cells, we observed a rapid increase in phosphatidic acid (PtdOH) levels right after stimulation, which was not observed in non-stimulated cells. The increase, however, was suppressed by wortmannin pre-treatment, which also inhibited amylase secretion. Changes in other major phospholipids were not significant. These results indicate that CCK-8 induces amylase secretion through PI3K-regulated production of PtdOH in cell membranes.
Ikeda
Yoshiki
Y
Department of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan.
Fukuoka
Shin-ichi
S
D000681:Amylases / Q000378:metabolism*; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002766:Cholecystokinin / Q000737:chemistry*; D002855:Chromatography, Thin Layer; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D010179:Pancreas / Q000166:cytology; D010712:Phosphatidic Acids / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010743:Phospholipids / Q000737:chemistry; D051381:Rats; D013997:Time Factors; D014407:Tumor Cells, Cultured; D000077191:Wortmannin
D000730:Androstadienes; D004791:Enzyme Inhibitors; D010712:Phosphatidic Acids; D010743:Phospholipids; D002766:Cholecystokinin; D019869:Phosphatidylinositol 3-Kinases; D000681:Amylases; D000077191:Wortmannin