2-Methoxy-4-nitroaniline is a selective inducer of cytochrome P450IA2 (CYP1A2) in rat liver

Male F344 rats were treated with a chemical (aniline, nitrobenzene, 2-methoxy-p-phenylenediamine, 2-methoxy-4-nitroaniline or 2-methoxy-4-nitroazobenzene) produced by the azo-reduction and/or N-oxidation of 2-methoxy-4-amino-azobenzene, a selective inducer of cytochrome P450IA2 (CYP1A2), and their effects on the induction of CYP1A enzymes in the liver were examined in terms of the protein and mRNA amounts. 2-Methoxy-4-nitroaniline and 2-methoxy-4-nitroazo-benzene, but not other compounds tested, induced CYP1A enzymes, especially CYP1A2, as assessed by Western blotting and Northern blotting. It is noteworthy that 2-methoxy-4-nitroaniline was more selective than 2-methoxy-4-aminoazobenzene for induction of CYP1A2, and it has the smallest molecular size among the known CYP1A2 inducers.