Genotoxicity of cycasin in the hepatocyte primary culture/DNA repair test supplemented with beta-glucosidase.

The genotoxicity of cycasin was examined in the standard hepatocyte primary culture (HPC)/DNA repair test and in the test supplemented with beta-glucosidase. Generally, no DNA repair was elicited by cycasin in the standard test except for one assay which showed a strong response. With the addition of beta-glucosidase to the test medium, cycasin elicited DNA repair with clear dependence on both dose and amount of beta-glucosidase. These results indicate that supplementation of the HPC/DNA repair test with the appropriate should be useful in detecting potentially genotoxic glucosides and suggests that supplementation with other specific enzymes could compensate for extrahepatic biotransformation processes required prior to final activation by hepatocytes.