The knowledge of pathobiochemical processes in extrahepatic cholestasis is one of the prerequisites for the application of infusion solutions adjusted to meet the requirements. Early changes of amino acid metabolism in rats after bile-duct ligation, which indicate disorders in the urea cycle are reported. For this purpose 60 male Wistar rats were laparotomized and the common bile duct was twice ligated under narcosis with pentobarbital. Exsanguination of the animals from the aorta abdominalis occurred after 3, 6, 12, 24, 48 and 72 hours. Analysis of the free amino acids in serum was performed by means of middle pressure liquid column chromatography at fully automatic analytical apparatus (Liquimat III, Kontron).
Results: Of 23 free amino acids investigated in serum only Ornithin and Arginin showed significant changes in their serum concentrations after ligature of the common bile duct. The increase of the serum concentration of Ornithin and the simultaneous decrease of Arginin suggests the inhibition of the urea cycle induced by resorptive jaundice. This might be due to the inhibition of the ATP-dependent, mitochondrial carbamyl phosphate synthetase or to the activation of the cytoplasmatic arginase.