INDUCTION OF MICRONUCLEI AND SISTER-CHROMATID EXCHANGE IN MOUSE SPLENOCYTES AFTER EXPOSURE TO THE BUTADIENE METABOLITE 3,4-EPOXY-1-BUTENE

3,4-Epoxy-1-butene (EB) is one of the main metabolites of 1,3 butadien e, a widely used industrial chemical, The mutagenic potential of 1,3 b utadiene and its metabolites have been studied in different test syste ms, In this work the genotoxic effects of EB were studied by estimatin g micronuclei (MN) and sister chromatid exchange (SCE) frequencies in stimulated mouse splenocytes. Mice were treated in vivo with various d oses of EB (24.4, 48.8 and 73.2 mg/kg). The antikinetochore antibody t echnique (CREST) was also applied to MN in cytokinesis blocked cells t o investigate any possible aneugenic effect, Both MN and SCE frequenci es increased after EB treatment. The induced MN resulted mainly from a centric fragments but a weak aneugenic effect was found as well. Cytot oxic effects of EB were observed at the highest dose. The above result s, in combination with others on the effect of 1,3 butadiene and its m etabolites in somatic and germ cells of mouse and rat as well as in so matic human cells, form a part of the information needed for applicati on of the parallelogram approach and extrapolation to human risk.