The liver is the main organ clearing both plasma and tissue kallikreins from the circulation. Hepatocytes are responsible for the internalization of rat plasma kallikrein (RPK) and the clearance of plasma kallikrein by the liver is Ca(2+)-independent. The binding site of RPK to the liver cell is located on its heavy chain which is not exposed on prokallikrein. An S-type lectin accounts for the receptor-mediated endocytosis of RPK. 2. These properties of the liver are affected by pathological situations, particularly the acute-phase response to inflammation, in which the kallikrein-kinin system plays a major role. The hepatic clearance of the alpha 2-macroglobulin-plasma kallikrein complex is less efficient than the clearance of the free enzyme.
