Sensitivity of rat and mouse peripheral blood lymphocytes to BaP adduction and SCE formation

Both mice and rats were injected i.p. with doses of benzo[a]pyrene (BaP) ranging from 10 to 100 mg/kg to compare species sensitivity to and the relationship between sister chromatid exchange (SCE) induction and DNA adduct formation. Twenty-four hours after injection, blood was removed by cardiac puncture and the peripheral blood lymphocytes (PBLs) were analyzed for both DNA adduct formation by 32P-postlabeling and SCE induction following lymphocyte culture. BaP induced similar, but not identical, SCE dose-response curves for each species. After BaP administration, the major DNA adduct, N2-[10 beta-(7 beta,8 alpha,9 alpha-trihydroxy-7,8,9,10- tetrahydrobenzo[a]pyrene)yl]deoxyguanosine (BPDEI-dGuo), was approximately 10-fold more prevalent in the PBLs of the mouse than those of the rat. Thus, for equivalent amounts of BPDEI-dGuo, a greater number of SCEs are induced in the rat than the mouse.