Effect of temperature on the P4501A response in winter- and summer-acclimated Arctic char (Salvelinus alpinus) after oral benzo[a]pyrene exposure

In this study, the time-dependent P450 response to oral benzo[a]pyrene expo sure at 1 and 10 degrees C was investigated in winter- and summer-acclimate d Arctic char (Salvelinus alpinus). In both seasons, a strong induction of CYP1A activities and protein levels (measured only in the winter experiment ) were seen at both 1 and 10 degrees C. At 1 degrees C, the responses were delayed and more long-lasting than at 10 degrees C. No within-season differ ence between 1 and 10 degrees C in the magnitude of the induction response was found, but due to elevated baseline CYP1A activities, the induction res ponse was seven times lower in winter- as compared with the response in sum mer-acclimated Arctic char. The results show that the CYP1A enzymes of the Arctic char respond to temperature changes in a compensatory way, and they are promising with respect to the applicability of the P450 enzyme system o f the Arctic char as a biomarker for monitoring polycyclic aromatic hydroca rbon contamination in high-latitude environments. More studies are needed, however, to reveal seasonal differences in the biomarker response to pollut ants.