Benzene is metabolized to a number of electrophilic species that are capable of binding to both DNA and proteins. We used adducts of hemoglobin (Hb) Although both mice and rats showed dose-related increases in Hb and bone marrow protein adducts of BO and of the two benzoquinones, large intertissue and interspecies differences were noted, suggesting different preferences in metabolic pathways. The highest levels of adducts in mice were of 1,4-BQ (10-27% of all cysteine adducts), while in rats, BO adducts predominated in Hb (73% of all cysteine adducts) and 1,2-BQ adducts predominated in the bone marrow (14% of all cysteine adducts). High background levels of 1,2-BO and 1,4-BQ adducts were also detected in both species, indicating that the toxic effects of quinone metabolites may only be important at high levels of benzene exposure.

No abstract