Increased Circulating Cholecystokinin in Obstruction-Induced Acute Pancreatitis: II. Pancreatic Duct Obstruction with and without Bile Duct Obstruction

Abstract

Pancreatic exocrine stimulation by cholecystokinin (CCK) has been implicated in pathogenesis of experimental acute pancreatitis. Bile exclusion from the gut stimulates duodenal CCK release and exacerbates obstruction-induced acute pancreatitis. Pancreatic and bile duct obstruction increases circulating CCK concentration. We hypothesized that acute pancreatitis induced by pancreatic and bile duct obstruction would be ameliorated when bile was returned to the duodenum. As many small pancreatic ducts drain into the bile duct in rats, preservation of bile flow required the use of a bile shunt. We studied acute pancreatitis and the time course of circulating CCK increase in three groups of rats after: (1) sham operation (dissection, no obstruction), (2) bile and pancreatic duct obstruction, and (3) bile and pancreatic duct obstruction with bile shunt. The rats were killed at 3-, 6-, and 18-hr intervals after operation. Their blood was collected for measurement of CCK, amylase, and bilirubin concentrations. The pancreata were excised, weighed, and processed for histological examination. The shunting of bile back to the duodenum ameliorated the acute pancreatitis along with a simultaneous limitation of the rise in CCK concentration. This suggests that bile duct obstruction, an other form of bile exclusion, exacerbates pancreatic duct obstruction-induced acute pancreatitis. The elevation in CCK concentration showed an early peak indicating that the potential role of CCK in the pathogenesis of obstruction-induced acute pancreatitis is predominantly in the early phase of its development.