Evaluation of liver and peripheral blood micronucleus assays with 9 chemicals using young rats. A study by the Collaborative Study Group for the Micronucleus Test (CSGMT)/Japanese Environmental Mutagen Society (JEMS)-Mammalian Mutagenicity Study Group (MMS).

Abstract We conducted simultaneous liver and peripheral blood micronucleus assays in young rats with seven rodent hepatocarcinogens—4,4′-methylenedianiline (MDA), quinoline, o -toluidine, 4-chloro- o -phenylenediamine (CPDA), dimethylnitrosamine (DMN), p -dimethylaminoazobenzene (DAB), and di(2-ethylhexyl)phthalate (DEHP)—and two mutagenic chemicals—kojic acid and methylmethanesulfonate (MMS). Quinoline, DMN, and DAB were positive in the liver assay, while o -toluidine, kojic acid, DAB, and MMS were positive in the peripheral blood assay. o -Toluidine, kojic acid, and DAB are reportedly negative in mouse bone marrow micronucleus assays, indicating a species difference. Our results revealed a correlation between micronucleus induction in hepatocytes and hepatocarcinogenicity. This technique can be useful for the detection of micronucleus-inducing chemicals that require metabolic activation, and it enables simultaneous comparison of the micronucleus-inducing potential of chemicals in the liver and peripheral blood in the same individual.