Li D, Chandar N, Lombardi B, Randerath K
Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030.
Carcinogenesis. 1989 Mar;10(3):605-7. doi: 10.1093/carcin/10.3.605.
Groups of rats were fed for 1, 4 or 7 months choline-devoid or choline-supplemented diets, that provided approximately 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 P1-enhanced version of the 32P-postlabeling assay, which detects aromatic/hydrophobic DNA adducts and I-compounds (adduct-like DNA modifications shown to accumulate in tissue 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.
将几组大鼠分别用缺乏胆碱或补充胆碱的饲料喂养1、4或7个月，这些饲料提供了约50%的蛋氨酸，以及幼龄生长大鼠胆碱需求量的0.15%或150%。分离肝脏DNA，并通过核酸酶P1增强版的32P后标记分析法进行分析，该方法可检测芳香族/疏水性DNA加合物和I型化合物（在衰老大鼠组织中积累的类似加合物的DNA修饰）。在喂食这两种饲料的大鼠中未观察到DNA加合物和I型化合物模式的定性差异。然而，与喂食对照饲料的大鼠相比，喂食缺乏胆碱饲料的大鼠中I型化合物的积累大幅减少。这些结果扩展了先前关于喂食缺乏胆碱饲料的大鼠肝脏中缺乏相关DNA加合物的证据，并表明I型化合物可能在这种饲料的致癌性中起作用。
