Influence of intraluminal trypsin activity on the course of acute experimental pancreatitis.

In short-term experiments (25 or 72 h) oral trypsin inhibitor administration to pancreatitic rats significantly decreased survival rate, whereas oral trypsin administration had no effect in this respect. Neither treatment influenced the activities of amylase in serum, pancreatic tissue or ascites. Trypsin given in excess together with the trypsin inhibitor abolished the deleterious effects on survival caused by the trypsin inhibitor. In a long-term experiment in healthy rats oral trypsin inhibitor ingestion caused a significant increase in pancreatic wet weight, protein concentration and activities of amylase, lipase and trypsinogen in pancreatic tissue; again, trypsin administration had no effect. The data support the idea that oral trypsin inhibitor administration causes release of cholecystokinin (CCK) or CCK-like factors from the intestine by interfering with the negative feedback regulation exerted by intraluminal trypsin. The results of the short-term experiments further indirectly suggest that even small amounts of trypsin within the intestine - as in acute pancreatitis - can exert the feedback regulation. Finally, the results of the long-term experiment suggest that oral administration of trypsin does not exert any suppressive effects on pancreatic wet weight and pancreatic enzyme content.