A kinetic model of mitochondrial aspartate aminotransferase transmigration in hepatobiliary disorders.

A hypothetical kinetic model of transmigration of mitochondrial aspartate aminotransferase (m-AST) from liver to blood and its elimination from blood was constructed and assessed for prediction by computer simulation. The elimination of m-AST from plasma in healthy rats followed first-order kinetics. Depletion of m-AST from the liver after induction of hepatobiliary disorders in rats with alpha-naphthylisothiocyanate (ANIT) also followed first-order kinetics. In contrast, the changes in metabolic rate in the liver after ANIT administration, as estimated from the plasma indocyanine green clearance, approximated to a second-order time function. Based on these data, the time-dependent change in plasma m-AST activity after ANIT administration was simulated by computer according to a hypothetical kinetic model. The result of computer simulation of the change in plasma m-AST coincided well with that obtained experimentally, suggesting that continuous measurements of m-AST may be helpful to the clinical diagnosis of liver injury.