Biosynthesis and release of prostaglandins by mast cells

Rat mast cells, isolated from peritoneal fluids, were found to release substantial amounts of immunoreactive E-type prostaglandin when stimulated in vitro by foetal calf serum or incubated in the presence of arachidonic acid. Extracellular accumulation of iPGE reflected synthesis, rather than release of preformed material, since it was abolished by indomethacin, a potent and relatively specific inhibitor of prostaglandin synthetase. Hydrocortisone and Compound 48/80, in such experimental conditions, did not affect PGE release.