Sex differences in the chemical induction of micronuclei in the rat.

Abstract

The micronucleus assay was conducted with 7 chemicals (2-acetylaminofluoren [2-AAF], 1-β-D-arabinofuranosylcytosine [Ara-C], colchicine, cyclophosphamide [CP], methyl methanesulfonate [MMS], potassium bromate [KBrO3], urethane) in male and female rats to determine whether the results varied with sex. Each chemical was administered twice orally, 24 h apart, to 5 rats in each of 3 dosage groups and collected bone marrow and peripheral blood 24 h later. Sex differences were observed in micronucleus induction in both polychromatic erythrocytes (bone marrow) and reticulocytes (peripheral blood), which we attributed to a sex difference in hematopoiesis. In spite of those differences, both sexes showed positive responses. We concluded that the rat is suitable for the micronucleus assay regardless of sex.