Intercellular variation in levels of adducts of aflatoxin B1 and G1 in DNA from rat tissues: a quantitative immunocytochemical study.

Adducts between aflatoxin B1 and G1 and DNA have been visualised and quantified in various rat tissues by a sensitive immunocytochemical approach. The quantitative validity of this assay has been examined by comparison with experiments using radioactively labelled aflatoxin. Rats were exposed to single and multiple doses of aflatoxin and a marked intercellular variation in adduct levels was observed in kidney and lung, in contrast to the liver, where binding was more homogeneous. No adducts were detected in the oesophagus, forestomach, colon, spleen or testes (detection limit approximately 300 pg aflatoxin/mg DNA). The DNA adduct data are discussed in relation to the carcinogenicity of aflatoxin B1 and G1.