[Influence of precursors of endogenously synthesized dimethylnitrosamine on the activity of the demethylase of that carcinogen in rat liver].

Oral administration of dimethylamine, sodium nitrite and a combination of these precursors of endogenously synthesized dimethylnitrosamine to rats increased the activity of demethylase of this carcinogen in the liver microsomes. Under conditions of chronic experiment inclusion of dimethylamine into the diet of rats intensified the demethylase activity even in the presence of casein, an inductor of this enzymatic system. An inhibitor of protein synthesis--actinomycin D prevented an increase of demethylase activity in the microsomal fraction caused by dimethylamine.