INDUCTION OF MICRONUCLEI AND SISTER-CHROMATID EXCHANGES IN SHEEP LYMPHOCYTE-CULTURES BY HERBICIDE CHLORIDAZON

The effect of herbicide chloridazon was studied using induction of mic ronuclei (MN) and sister chromatid exchanges (SCE) in vitro. Induction s of these markers were measured in sheep peripheral lymphocytes with and without of metabolic activation (S-9 mix). Chloridazon affected bo th MN and SCE at all of the concentrations tested. Significant increas es (P<0.05) were achieved at 7 x 10(-4) M in both tests. Neither of th e lower concentrations (7 x 10(-5) M and 7 x 10(-6) M) did affect the MN or SCE values. The herbicide was also tested in presence of an S 9 mix activating fraction, in which significant increases of SCE levels were determined for concentrations of 7 x 10(-5) M and 7 x 10(-4) M (P <0.05 and 0.01, respectively). No induction of the cell cycle delay or reduction of proliferation index (PI) were detected. Chloridazon has, as shown in our assays, a weak influence on induction of tested chrom osomal changes.