Prostaglandins and enzyme secretion from dispersed rat pancreatic acinar cells

The role of prostaglandins in exocrine pancreatic enzyme secretion was studied. The effects of three inhibitors of prostaglandin and thromboxane syntheses, were evaluated on release of amylase from dispersed rat pancreatic acinar cells. Mepacrine inhibited, while indomethacin and imidazole had no effect on basal or carbachol or cholecystokinin stimulated enzyme release. Exogenous arachidonic acid or various prostaglandins (E₁, E₂, F_2α, I₂), also did not affect the secretory process. Acinar cells actively incorporated radioactive arachidonic acid, principally into phospholipids (especially phosphatidylcholine), however release of the free fatty acid and subsequent synthesis of radioactive endogenous prostaglandins was not stimulated by the presence of different pancreatic stimulants. Pancreatic microsomes were found to be lacking in cyclo-oxygenase, an enzyme involved in endegenous synthesis of prostaglandins. The data suggest that prostaglandins are not involved directly in excitation-secretion coupling in the exocrine pancreas.