Human hepatocytes in genotoxicity assays.

Human hepatocyte primary cultures, because of their comprehensive biotransformation capability, represent an experimental model particularly useful to gain direct information on the genotoxic risk of chemicals to humans. For this purpose they have been used in the last few years either as target cells to evaluate the induction of DNA damage and/or DNA repair synthesis, or as metabolic activation system in mutagenicity assays. The number of compounds so far tested is rather limited, and for the large majority of them the assays have been performed only on hepatocytes from a few donors. A comparison with the data obtained in rat hepatocytes indicates that quantitative differences in the genotoxic effects induced in cultures derived from different donors of the same species are usually greater than interspecies differences. However, the results.provided by some chemicals suggest the possibility that in certain cases rat hepatocytes might be inappropriate predictors of the genotoxic hazard for humans.