DETECTION OF THE CENTROMERE IN MICRONUCLEI BY FLUORESCENCE IN-SITU HYBRIDIZATION - ITS APPLICATION TO THE HUMAN LYMPHOCYTE MICRONUCLEUS ASSAY AFTER TREATMENT WITH 4 SUSPECTED ANEUGENS

The human lymphocyte micronucleus (MN) test combined with fluorescence in situ hybridization (FISH) of a centromeric probe is considered a u seful screening assay to distinguish between clastogenic and aneugenic agents. Four suspected aneuploidy-inducing chemicals, acetaldehyde (A A), diethylstilbestrol (DES), diethylstilbestrol dipropionate (DESdp) and griseofulvin (GF), have been evaluated with the assay, All compoun ds induced a significant increase of MN at all doses tested. After the application of the FISH technique with a pancentromeric DNA sequence, DES, DESdp and GF showed a statistically significant increase in the percentage of positive signals compared with the control culture, GF i nduced the highest percentage of centromere-positive MN observed to da te (>90% on average), AA did not show a significant difference in the percentage of centromere-positive MN. The results indicate that in hum an lymphocytes DES, DESdp and GF act primarily as aneugens, while AA s eems capable of causing both chromosome breakage and aneuploidy.