[Clinico-chemical diagnosis of the cholestasis syndrome]

1. Cholestatic reactions of various etiology are biochemically established by determination of alkaline phosphatase, gamma-glutamyltranspeptidase (and leucinaminopeptidase) activities and of bile acid concentrations in serum. 2. The pathomechanisms of elevated serum activities of AP, gamma-GT and LAP in cholestatic diseases are - an induction of these canalicular membrane bound enzymes, probably due to an intracellular increase of bile acids, - a partial solubilization of canalicular membrane structure (detergent effect of bile acids), - a histochemically and morphologically demonstrable change of liver cell polarity. 3. A discrimination of intra- or extrahepatic cholestasis only by means of biochemical parameters is impossible. 4. Additional serological and immunological parameters often demonstrate the etiology of cholestatic diseases; a short review is given.