The effect of 7H-dibenzo[c, g]carbazole and benzo[a]pyrene mixture on DNA adduct formation in strain A/J mouse model: Preliminary report

Complex mixtures consist of homocyclic and heterocyclic polycyclic aromatic compounds (PACs) represented by benzo[a]pyrene (BaP) and 7H-dibenzo[c,g]carbazole (DBC), respectively. To exert their biological effects, PACs are metabolized into reactive intermediates, which can form DNA adducts. In this preliminary report, male A/J mice were given a single intraperitoneal injection. Groups of three animals were treated with DBC (2 or 10 mg/kg) or BaP (10 or 100 mg/kg). Mixtures of DBC:BaP were given at doses o 2:10, 2:100, 10:10, or 10:100 mg/kg. DNA adduct levels in lungs collected three days posttreatment were determined by the ³²P-postlabeling method. The results indicate that, in the lungs, exposure to mixtures containing more BaP than DBC resulted in the absence of adduct 3 (DBC) and significantly higher total adduct levels. This suggests that BaP is being preferentially metabolized, resulting in less DBC adduction.