Pancreatic phospholipase A2 in cerulein-induced acute pancreatitis in the rat.

We investigated the concentration of immunoreactive pancreatic phospholipase A2 (pan-PLA2) and the catalytic activity of phospholipase A2 (CA-PLA2) in plasma and pancreases of rats with cerulein-induced acute pancreatitis. Edematous pancreatitis with ascites and fat necroses in the abdominal cavity developed after 8 h infusion of cerulein (5 micrograms/kg/h). Large vacuoles were found in acinar cells and there were small areas of acinar cell necrosis. No pathological changes were seen in saline-infused control animals. Pancreatic PLA2 was localized by immunohistochemistry in pancreatic acinar cells in both groups of animals and in the proximal tubular cells of the kidney in cerulein-infused animals. The lungs and kidneys appeared normal by light microscopy in all animals. The pan-PLA2 values increased markedly, whereas the CA-PLA2 values did not change during the cerulein-infusion. The CA-PLA2 values in the homogenates of pancreatic tissue of cerulein-infused animals did not differ significantly from those of saline-infused controls. The results indicate that the CA-PLA2 in plasma is independent from the concentration of pan-PLA2 in cerulein-induced acute pancreatitis in rat.