[Changes in the isoenzymatic makeup of pyruvate kinase in hepatic carcinogenesis].

Together with an increase in the total activity of pyruvate kinase, alterations in the isoenzyme spectrum were observed in hepatocarcinogenesis caused by treatment of rats with diethylinitrosamine. The alterations might be divided into two steps: initial, reversible changes and changes immediately related to development of the blastomatous process. The total activity of pyruvate kinase was gradually increased with appearance of hyperplastic symptoms as well as of primary tumoral foci in liver tissue. The M2-type of pyruvate kinase tended to exhibit activation. In primary hepatomas the L-type of the enzyme was decreased and activity of the M2-type was increased.