Sister-chromatid exchanges induced by 1.3-butadiene and its epoxides in CHO cells.

Sister-chromatid exchanges (SCEs) were analyzed in CHO cells after pulse treatment with 1,3-butadiene, 3,4-epoxy-1-butene (monoepoxybutene) and 1,2:3,4-diepoxybutane (diepoxybutane). A weak dose effect was observed after exposure to 1,3-butadiene but only in the presence of S9 mix. Monoepoxybutene and diepoxybutane were highly effective in inducing SCEs at concentrations of 0.1-1 microM both in the presence and in the absence of S9 mix. At higher concentrations the response was more pronounced without S9 mix.