Pancreatic inschemia, especially due to pancreatic microcirculation disturbance, has been considered to trigger and aggravate acute pancreatitis. In this work experimental acute pancreatitis was produced by autologous bile and trypsin in mongrel dogs to study the time-course changes in systemic and local hemodynamics in association with disease progress. In addition, the effects of a new synthetic pancreatic protease inhibitor (PATM, 3 mg/kg/hr, i.v.) on systemic and local circulation were examined. In animals with untreated pancreatitis the mean baseline pancreatic microflow was 55.6 +/- 17.0 ml/min/100g before the onset of pancreatitis and this decreased by 22% and 52% at 1 hr and 5 hr, respectively. The femoral arterial pressure and cardiac index also decreased during the 5 hr experiment at period in comparison with the respective preoperative levels. The portal venous flow showed a sharp reduction immediately after the onset of pancreatitis, staying at a low level thereafter. The pancreatic microflow was significantly improved by PATM treatment for the first 60 min and the portal venous flow for the first 120 min. PATM treatment prevented the decrease in femoral arterial pressure, although it failed to exert any appreciable effect upon the cardiac index. These findings suggest that intravenous administration of PATM might be of value for improving the pancreatic microflow and portal venous flow, at least in the early stage of experimental acute pancreatitis in dogs.