MEASUREMENT BY P-32 POSTLABELING OF (+/-)ANTI-BENZO[A]PYRENE-DIOLEPOXIDE-N-2-DEOXYGUANOSINE ADDUCT PERSISTENCE IN UNSTIMULATED HUMAN PERIPHERAL-BLOOD LYMPHOCYTES

In order to study the relative importance of endogenous and environmental factors for the individual relation between DNA damage and DNA excision repair, a method was developed for measuring quantitatively the persistence of N-2-deoxyguanosine adducts formed in non-stimulated isolated human peripheral blood lymphocytes after in vitro incubation with 0.2 mu M (+/-)anti-BPDE, applying P-32-postlabeling. Total binding of radiolabeled (+/-)anti-BPDE to DNA and its removal has been studied previously in human peripheral blood lymphocytes, but the method presented here enables the direct investigation of repair of the main (+/-)anti-BPDE-DNA adduct, which is implicated in benzo[a]pyrene-induced mutagenesis. Using this method, it was found that in lymphocytes, obtained from 5 individuals, most (+/-)anti-BPDE-N-2-dG adducts are removed within the first 24 h after treatment, while interindividual differences appear to exist in both adduct formation and rate and extent of removal.