Chymotrypsin-like activity in rat tissues in experimental acute pancreatitis.

PURPOSE Increase in intracellular chymotrypsin activity was reported during acute pancreatitis. Beside chymotrypsin, there are at least two enzymes with chymotrypsin-like activity: proteasome and lysosomal cathepsin A. Until now it is not known whether and to what extent they contribute to increases in chymotrypsin activity in acute pancreatitis. Our aim was to study organ chymotrypsin-like activities during experimental acute pancreatitis. MATERIAL AND METHODS Rat cerulein model of acute pancreatitis was used. The chymotrypsin-like activities were assessed in pancreas, liver, lung, heart, spleen and kidney using highly selective synthetic substrates of the proteasome and the cathepsin A, at neutral and acidic pH. Determinations after addition of selective inhibitor were also performed. RESULTS During acute pancreatitis we found in the pancreas an increase only in neutral chymotrypsin-like activity, as compared to the control animals. In other organs neutral chymotrypsin-like activity did not increase, and in kidney it even decreased. There were no changes in acidic chymotrypsin-like activity in any of organs studied. The studies using the inhibitor of the proteasome showed that the neutral chymotrypsin-like activity in the pancreas of the rats with acute pancreatitis should not be attributed to the proteasome activity, but rather to the chymotrypsin. CONCLUSIONS Our results did not confirm any significant contribution of proteasome or cathepsin A to increased chymotrypsin-like activity in acute pancreatitis. We showed a decrease in neutral chymotrypsin-like activity of proteasome in the kidney, but the significance of this finding remains to be established.