The environmental pollutant benzo[a]pyrene (BaP) is a human carcinogen that reacts with DNA after metabolic activation catalysed by cytochromes P450 (CYP) 1A1 and 1B1 together with microsomal epoxide hydrolase. The azo dye Sudan I is a potent inducer of CYP1A1/2. Here, Wistar rats were either treated with single doses of BaP (150 mg/kg bw) or Sudan I (50 mg/kg bw) alone or with both compounds in combination to explore BaP-derived DNA adduct formation in vivo. Using 32P-postlabelling, DNA adducts generated by BaP-7,8-dihydrodiol-9,10-epoxide were found in livers of rats treated with BaP alone or co-exposed to Sudan I. During co-exposure to Sudan I prior to BaP treatment, BaP-DNA adduct levels increased 2.1-fold in comparison to BaP treatment alone. Similarly, hepatic microsomes isolated from rats exposed to Sudan I prior to BaP treatment were also the most effective in generating DNA adducts in vitro with the activated metabolites BaP-7,8-dihydrodiol or BaP-9-ol as intermediates. DNA adduct formation correlated with changes in the expression and/or enzyme activities of CYP1A1, 1A2 and 1B1 in hepatic microsomes. Thus, BaP genotoxicity in rats in vivo appears to be related to the enhanced expression and/or activity of hepatic CYP1A1/2 and 1B1 caused by exposure of rats to the studied compounds. Our results indicate that the industrially employed azo dye Sudan I potentiates the genotoxicity of the human carcinogen BaP, and exposure to both substances at the same time seems to be hazardous to humans.

• Keywords
• DNA-adducts, Sudan I, benzo[a]pyrene, cytochromes P450 1A1 and 1A2 and 1B1, genotoxicity, microsomal epoxide hydrolase,
• MeSH
• DNA Adducts toxicity   MeSH
• Coloring Agents toxicity   MeSH
• Benzo(a)pyrene toxicity   MeSH
• Cytochrome P-450 CYP1A1 metabolism   MeSH
• Microsomes, Liver drug effects   MeSH
• Liver drug effects   MeSH
• Carcinogens, Environmental toxicity   MeSH
• Rats MeSH
• Naphthols toxicity   MeSH
• Rats, Wistar MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• 1-phenylazo-2-naphthol MeSH Browser
• DNA Adducts MeSH
• Coloring Agents MeSH
• benzo(a)pyrene-DNA adduct MeSH Browser
• Benzo(a)pyrene MeSH
• Cytochrome P-450 CYP1A1 MeSH
• Carcinogens, Environmental MeSH
• Naphthols MeSH