[Enzymes of the Xenobiotic Metabolism of Continuous Cell Lines in invitro Toxicity Testing]

Cells in continuous culture contain a large number of enzymes which are involved in the metabolism of potentially toxic chemicals. As a rule, the activities of these enzymes represent functions of low tussle specificity. In contrast, those functions which are specialized "differentiated" functions in vivo are no longer expressed in continuous cell lines. However, an increasing number of observations indicates that cell lines may also contain these functions. Cell lines which lack or possess specific xenobiotic metabolizing enzymes are already applicable for analyzing the complex mechanisms of activation and inactivation of chemicals. With a better understanding how differentiated cell functions are regulated, prospects are promising for establishing metabolically competent cell lines, which can also be used in the screening of toxic chemicals.