Cytogenetic effects of the herbicide chloridazon in cultured sheep lymphocytes

The effect of in vitro exposure to the herbicide chloridazon on the induction of chromosome aberrations (CA) and sister chromatid exchanges (SCE) was studied in cultured sheep peripheral lymphocytes. A positive clastogenic effect was observed in chloridazon-treated cultures at a dose of 7 x 10(-4) M both in the presence and absence of the S9 fraction, but no significant increase of chromosome breaks was seen at lower doses (7 x 10(-6) M and 7 x 10(-5) M, respectively). A clear dose-dependence and significant differences were found in chloridazon potency to induce SCEs. Induction of cell cycle delays as compared to the controls was not observed.