COMPARISON OF CYP1A1 INDUCTION AND GENOTOXICITY IN-VITRO AS INDICATORS OF POTENTIALLY HARMFUL EFFECTS OF ENVIRONMENTAL-SAMPLES

Cytochrome P450IA1 (CYP1A1) induction of Hepa-1 mouse and H4IIE rat he patoma cell Lines was compared using selected environmental samples. T he re- sults were in agreement for both cell lines: no induction was o bserved for the fly ash extract from peat combustion, an intermediate induction was found for the fly ash extract from biosludge combustion, and a strong induction was detected for natural peat extract. However , Hepa-1 responded to the samples more sensitively than did H4IIE: the half maximal induction (ED(50)) values for Hepa-1 were smaller than t hose for H4IIE. In a bacterial DNA repair assay without metabolic acti vation and in a mammalian sister chromatid exchange test in the presen ce of metabolic activation the samples were virtually non-genotoxic. T hus the CYP1A1-inducing potency and genotoxicity of the samples were n ot correlated. In light of these results, the CYP1A1 induction test mi ght be a useful addition to conventional genotoxicity tests, which may fail to detect potentially harmful compounds/mixtures.