title: Age- and tissue-related DNA modifications in untreated rats: detection by 32P-postlabeling assay and possible significance for spontaneous tumor induction and aging.
abstract: When liver, kidney, lung and heart DNA preparations of untreated Sprague-Dawley rats of different ages (3 days-10 months) were analyzed for the possible presence of covalent modifications by a 32P-postlabeling assay, characteristic tissue-specific patterns of 32P-labeled spots (termed I-spots) were observed on thin-layer chromatograms. Amounts of these DNA derivatives (termed I-compounds), which were not detected in newborn rat DNA, markedly increased with age. This novel type of DNA modification could be due to environmental (e.g. dietary) factors or to endogenous DNA-reactive metabolites and may conceivably play a role in the initiation of spontaneous cancers or other adverse health effects related to aging.
mesh_terms: D000375:Aging; D000818:Animals; D002273:Carcinogens / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D009369:Neoplasms / Q000209:etiology*; D010761:Phosphorus Radioisotopes; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002273:Carcinogens; D010761:Phosphorus Radioisotopes; D004247:DNA