High levels of
benzo(a)pyrene diol
epoxide (
BPDE)-DNA adducts in white blood cells have been indicated as a risk factor for
lung cancer. Sensitive, specific, fast and cost-efficient techniques for the detection of
BPDE-DNA adducts in white blood cells are required for routine human biomonitoring. In the present study, an immunoassay based on CE/LIF was developed for the detection of
BPDE-DNA adducts in mononuclear white blood cells (MNCs). Although
glutathione (GSH) conjugation catalyzed by
glutathione-S-transferase (GST) is considered to be the major pathway for inactivating
BPDE, the effect of GSH depletion on
BPDE-DNA adduct formation in MNCs has not been assessed. Therefore, we applied the newly developed method to study the effect of GSH depletion by D,L-
buthionine-[S,R]-sulfoximine (BSO) on the level of
DNA adducts. We found that pretreatment of MNCs with 150 microM BSO for 2 h prior to
BPDE exposure increased the level of
BPDE-DNA adducts appreciably (by approximately 70%). Further investigations revealed that the 2-h BSO treatment neither decreased the GSH level instantly nor affected GST activity; rather, it prevented the induction of GSH in response to subsequent
BPDE incubation. The blocked synthesis of GSH might be responsible for the elevated level of
BPDE-DNA adducts in MNCs after BSO and
BPDE treatment.