Local kallikrein and trypsin responses in the rat

1 Locally administered commercial hog pancreatic kallikrein (Depot-Glumorin) and bovine pancreatic trypsin both increased vascular permeability in the skin and paws of rats. 2 By the use of numerous antagonists and enzyme inhibitors, this vascular response was found to be the result not of kinin formation but of a direct action mostly on histamine receptors. 3 Highly purified kallikrein did not increase vascular permeability in rats, suggesting either that the effect was due to an impurity in the commercial preparation or that a structural change in the enzyme occurred on purification. 4 Soya bean trypsin inhibitor prevented the trypsin response when both were injected locally. On intraperitoneal injection, the inhibitor was effective only against local kallikrein. 5 The kallikrein inhibitor, aprotinin (Trasylol), was not effective against local kallikrein but it reduced the trypsin response when both were injected locally.