These results suggest the following: ET-1 is produced in and around the pancreas, mainly by endothelial cells, in severe acute pancreatitis; in the inflammatory setting, cytokines, activated thrombin and trypsin, may stimulate ET-1 production in a paracrine fashion; produced ET-1 may exaggerate the splanchnic microcirculation; and progressive ischemia may lead to necrosis of the pancreas and intestine.