[Substrate and hormonal induction of tryptophan pyrrolase detected in hepatoma 22a cells during transplantation to C3HA mice immunized with syngeneic liver antigens].

Tryptophan pyrrolase (TP), which counts to the marker enzymes of the liver, failed to occur in the cells of hepatoma 22a transplanted into intact C3HA mice. In mice previously immunized with syngenic liver homogenate, 38.9% of hepatomas had a TP level reaching, on the average, 36.2% of that in the intact mice liver. Substrate induction increased the percentage of TP tumors in immunized animals up to 75%, and their average enzyme activity up to 56.9%. No hormonal induction of TP could be proved in hepatoma 22a cells.