Involvement of endogenous cholecystokinin in the development of acute pancreatitis induced by closed duodenal loop

Involvement of endogenous cholecystokinin (CCK) in the development of acute pancreatitis induced in rats by closed duodenal loop (CDL) was examined, and the effects of the potent and specific CCK receptor antagonist loxiglumide on this model of acute pancreatitis were evaluated. Plasma CCK bioactivity was markedly elevated 3 and 6 h after onset of acute pancreatitis. A single subcutaneous injection of 50 mg/kg body wt of loxiglumide 30 min before the induction of acute pancreatitis completely eliminated the hypercholecystokinemia. Loxiglumide given 3 h after the induction of acute pancreatitis suppressed plasma CCK bioactivity, which had risen up to 30-fold over basal value (0 h) at 3 h, to nearly the basal level. Loxiglumide pretreatment, in addition, significantly prevented the rise in serum amylase and lipase activity, as well as the increase in ascitic volume. It also ameliorated histological alterations of hemorrhagic and necrotizing pancreatitis. Reduction of plasma CCK bioactivity by loxiglumide after the onset of pancreatitis slowed the rate of progression of pancreatitis. However, pancreatic wet weight and cellular infiltration were not significantly influenced by loxiglumide treatment. These observations suggest that endogenous CCK is not involved in the initiation of acute hemorrhagic and necrotizing pancreatitis induced by CDL, but is involved in the development of pancreatitis in this model.