Polychlorinated biphenyls pattern analysis: Potential nondestructive biomarker in vertebrates for exposure to cytochrome P450-inducing organochlorines

Biomarkers are valuable instruments to assess the risks from exposure of or ganisms to organochlorines. In general, however, these biomarkers are eithe r destructive to the animal of interest or extremely difficult to obtain ot herwise. In this paper, we present a nondestructive biomarker for exposure to cytochrome P450-inducing organochlorines. This marker is based on a patt ern analysis of metabolizable and nonmetabolizable polychlorinated biphenyl (PCB) congeners, which occur in several kinds of tissues (and even blood) that can be obtained without serious effects on the organism involved. The fraction of metabolizable PCB congeners is negatively correlated with expos ure to PCBs, which are known to induce specific P450 isoenzymes. This relat ion can be modeled by a logistic curve, which can be used to define critica l levels of exposure. In addition, this method creates an opportunity to an alyze biomarker responses in archived tissues stored at standard freezing t emperatures (- 20 degrees C), at which responses to established biomarkers deteriorate. Furthermore, this method facilitates attribution of the enzyme induction to certain classes of compounds.