Benzo(a)pyrene diol-epoxide-DNA adduct levels and aryl hydrocarbon hydroxylase (AHH) in human white blood cells from smokers and non-smokers

Benzo(a)pyrene diol-epoxide (BPDE)-DNA adducts and aryl hydrocarbon hydroxy lase (AHH) activity were determined in white blood cells (WBCs) obtained fr om non-smokers, ex-smokers and smokers. DNA adduct levels ranged from non-d etectable (ND) to 8.8 per 10(8) nucleosides in all samples analysed. The me an level in WBC from smokers (1.93 +/- 0.55 mean +/- SE) was similar to tha t from non-smokers (1.18 +/- 0.40) and ex-smokers (1.83 +/- 0.50). The dist ribution frequency of AHH activity in non-smokers was different from that i n smokers, while 50% of non-smokers had AHH activity ranging from ND to 20 fmol mg(-1) min(-1). This low AHH activity was not found in smokers; no cor relation was found between AHH activity and tobacco consumption (r=0.097; P = 0.76; n = 12). On the contrary, AHH activity was correlated with BPDE-DN A adduct levels in WBCs from the same subjects (r = 0.457; P = 0.019; n = 2 6). Our findings indicate that there are limitations to the use of WBCs as surrogate cells for determining internal PAH exposure in target organs.