[Effect of chemical hepatic carcinogens and noradrenaline on the nucleoside phosphokinase activity of liver cells].

Distinct increase in activity of uridine kinase and pronounced decrease in thymidine kinase activity were observed in cell-free extracts of rat liver tissue at early stages of hepatocarcinogenesis caused by administration of N-nitrose diethylamine and 2-acetyl aminofluorene. Exogenous noradrepaline did not affect the altered activity of thymidine kinase but stimulated the effect of N-nitrose diethylamine and lowered the effect of 2-acetyl aminofluorene on the urindine kinase activity. Adrenergic neurotransmitters appear to influence the cell proliferation due to modification of the enzymes participating in the synthesis of nucleic acid precursors.