The level of the zymogen granule protein GP2 is elevated in a rat model for acute pancreatitis.

GP2 is the major membrane protein in pancreatic zymogen granules. It is linked to the membrane via a glycosyl-phosphatidylinositol linkage. After cleavage, a significant fraction of GP2 becomes soluble. The present study assessed whether GP2 is a useful serum marker for acute pancreatitis. Using an anti-GP2 monoclonal antibody, an enzyme-linked immunosorbent assay was developed to measure the serum levels of GP2 in rats with cerulein-induced acute pancreatitis. The anti-GP2 antibody was specific because it did not cross-react with uromodulin, a structurally similar protein to GP2, or to protein extracts from nonpancreatic tissues. Eight hours after the induction of pancreatitis, the serum levels of amylase, lipase, and GP2 peaked. Peak GP2 levels were 4.2 times higher than those of controls. At 24 hours, GP2 was still 70% of the peak level, whereas amylase and lipase were 5.5% and 0.5%, respectively, of their peak levels. GP2 may serve as a potentially valuable marker for clinical acute pancreatitis.