Reduced accumulation of I-compounds in liver DNA of rats fed a choline-devoid diet.

Groups of rats were fed for 1, 4 or 7 months choline-devoid or choline-supplemented diets, that provided ∼50% of the methionine, and 0.15% or 150% of the choline requirements of young, growing rats. liver DNA was isolated and analyzed by the nuclease Pl-enhanced version of the P-postlabeling assay, which detects aromatk/hydrophobic DNA adducts and I-compounds (adduct-like DNA modifications shown to accumulate in tissues of aging rats). DNA adducts and qualitative differences in the patterns of I-compounds were not observed in rats fed the two diets. However, in rats fed the choline-devoid diet there was a drastic reduction in the accumulation of I-compounds, compared with that in rats fed the control diet. These results extend previous evidence of a lack of relevant DNA adducts in the liver of rats fed the choline-devoid diet, and suggest the possibility of a role of I-compounds in the carcinogenicity of this diet. [ABSTRACT FROM PUBLISHER]