The proteinases and proteinase inhibitors in the peritoneal exudate during acute experimental pancreatitis in the rat.

The proteolytic activities and trypsin inhibitors of the peritoneal exudate produced by experimental acute pancreatitis in the rat were studied by fractionation with gel filtration on Sephadex G-200 and estimation of the hydrolysis of casein and synthetic substrates. The peritoneal exudate produced by injecting formalin solution into the peritoneal cavity was used as a control. The peritoneal exudate during pancreatitis revealed distinct proteolytic and ATEE hydrolysing activities and it also hydrolysed BAPNA to a lesser extent. These activities were absent from the control exudates, or only traces of them could be demonstrated with the methods used. The trypsin inhibiting capacity (TIC) in the pancreatic exudate was about half that in the control exudate. In gel filtration on Sephadex G-200 the BAPNA hydrolysing proteolytic activity was eluted with the macroprotein fraction, suggesting that the enzyme was bound to the macroproteins. TIC differed clearly in the control exudate and the pancreatitis exudate. In both of them TIC was eluted in two peaks after the macroproteins, but in the pancreatitis group the first peak was very weak, if demonstrable at all, while in the control exudate the two peaks were clearly separated and the TIC was more pronounced. These findings suggest that pancreatic enzymes are released during pancreatitis into the peritoneal cavity, where they combine with proteinase binding factors in the exudate.