o-Aminoazotoluene does induce the enzymes of its own mutagenic activation in mouse liver.

Olga N Mikhailova, Elena A Vasyunina, Ludmila P Ovchinnikova, Lyudmila F Gulyaeva, Olga A Timofeeva, Maxim L Filipenko, Vasily I Kaledin

Index: Toxicology 211(1-2) , 132-8, (2005)

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Abstract

The objective of this study was to investigate the CYP1A1 and CYP1A2 mRNAs and enzyme activities in mouse liver during induction with o-aminoazotoluene (OAT) as well as the capability of the hepatic S9-fraction from OAT-treated mice to induce its own activation to mutagens in the Ames test using S. typhymurium strain TA98. The data obtained indicate that when used at appropriate doses, OAT is a PAH-type inducer of mouse hepatic microsomal monooxygenases, which activity is not less than that of the known inducer 3,4-benzo[alpha]pyrene. In the absence of S9-fraction enzymes no OAT-mediated mutagenicity was observed in the Ames test. In the presence of the S9-fraction from OAT-pretreated mice, OAT induced as high revertant numbers, as it did in the presence of the S9 fraction from the liver of Aroclor 1254-treated mice. Thus, OAT does induce the enzymes of its own mutagenic activation in mouse liver.