Effects of dietary choline deficiency on the mutagenic activation of chemical carcinogens by rat liver fractions.

Salmonella mutagenesis assays were used to evaluate the mutagenicity of several chemical carcinogens as mediated by liver S-9 fractions from rats fed a choline-supplemented (CS) or choline-devoid (CD) diet. The liver S-9 fraction from CD diet-fed rats was found to have a significantly decreased ability to activate 2-acetylaminofluorene (2-AAF), 2-aminoanthracene (2-AA) and 6-aminochrysene (6-AC), but not N-hydroxy-2-acetylaminofluorene (HO-N-2-AAF) and dimethylnitrosamine (DMN). The same liver S-9 fraction was also less effective in deactivating N-methyl-N1-nitro-N-nitrosoguanidine (MNNG) but not methylnitrosourea (MNU). A decrease (20%) in the cytochrome P-450 content was found in liver microsomes of CD diet-fed rats. Although it has been shown that feeding a CD diet to rats enhances chemical hepatocarcinogenesis, the data presented here suggest that CD diet does not increase the activation of the chemical procarcinogens tested.