This study investigates the role of platelet-activating factor (PAF) in experimental pancreatitis. The concentration of PAF quantified in ascites of bile-induced pancreatitis by radioimmunoassay (RIA) ranged from 3.67 +/- 0.39 pmol/mL 2 h to 0.954 +/- 0.39 pmol/mL 10 h after injection of taurocholate. Administration of a potent PAF antagonist, WEB-2170, prior to injection of taurocholate prolonged mean survival time in rats receiving i.v. camostate and albumin (46.4 h, n = 15, vs controls 38.3 h, n = 13). However, the survival rate after 72 h was not improved. The histologically estimated severity of pancreatitis and pancreatic enzymes in blood, tissue, or ascites was not affected. WEB-2170 had no effect on survival when injected simultaneously with taurocholate into the pancreatic duct or given i.v. after induction of pancreatitis (1, 0.1, or 0.01 mg/kg WEB-2170 vs controls). Subcutaneous injection of 10 mg/kg WEB-2170 also did not improve survival in pancreatitis induced by choline-deficient, ethionine-supplemented diet in mice. It is concluded that administration of a PAF antagonist after the onset of severe experimental pancreatitis does not influence its outcome, although activation of PAF may play a role in the pathogenesis of pancreatitis.