37 Journal of Toxicology and Environmental Health, Part A, 69:37–52, 2006 Copyright© Taylor & Francis Inc. ISSN: 1528–7394 print / 1087–2620 online DOI: 10.1080/15287390500259053 TO XICO KINETICS AND EFFECTS O F PCBs IN ARCTIC FISH: A REVIEW O F STU D IES O N ARCTIC CHARR Even H. Jørgensen 1,2 , Mathilakath M. Vijayan 3 , Jan-Eirik A. Killie 2 , Neelakanteswar Aluru 3 , Øyvind Aas-Hansen 4 , Alec Maule 5 1 Norwegian Institute for Nature Research, The Polar Environmental Center, Tromsø, Norway 2 Norwegian College of Fishery Science, University of Tromsø, Tromsø, Norway 3 Department of Biology, University of Waterloo, Waterloo, Ontario, Canada 4 Norwegian Institute of Fisheries and Aquaculture Research, Tromsø, Norway 5 USGS-BRD, WFRC, Columbia River Research Laboratory, Cook, Washington, USA In a series of environmentally realistic laboratory experiments, toxicokinetics and effects of polychlo- rinated biphenyls (PCBs) were studied in the Arctic charr (Salvelinus alpinus) . Winter fasting and emaciation, which are common among Arctic charr living in high latitudes, resulted in a redistribu- tion of the lipophilic PCBs from lipid-storing tissue such as the muscle, to vital organs that must be considered sensitive toward PCB (liver and brain). This redistribution was accompanied by a signifi- cant potentiation of the hepatic cytochrome P-450 (CYP) 1A biomarker response, from low activi- ties in October (within those measured in uncontaminated charr) to a high, probably maximum, induction in May. Performance studies demonstrated a clear effect of environmentally realistic PCB levels on endocrine mechanisms, immune function, and seawater preadaptation (smoltification) in charr that had been feed deprived for several months after contamination with Aroclor 1254, whereas a high PCB dose exerted only minor, if any, effects in charr that had been fed after contam- ination. These results demonstrate that emaciation results in decreased dose-response relationships in fish, and indicate that arctic animals undergoing seasonal cycles of “fattening” and emaciation may be extra sensitive toward persistent, lipophilic organochlorines. Pilot studies on Arctic charr from Bjørnøya Island revealed marked CYP1A biomarker responses and an upregulation of genes involved in cellular homeostatic mechanisms in charr from Lake Ellasjøen (high PCB levels). Thanks are extended to the staff at Talvik Research Station, and at Kårvik Research Station, for their skilled production of Arctic charr smolts and proper care of the fish during the experiments. We thank Judith Wolkers, Hans Wolkers, Jo Espen Tau Strand, and Steve Wiseman for help with analyses, and John Leather- land, who kindly provided us access to his laboratory for GH analyses. Thanks are also extended to Anita Evenseth and Guttorm Christensen for capturing fish for us at Bjørnøya.The study was supported by funding from the National Science Foundation, USA, project OPP-9908890; the Norwegian Research Council, projects 114263/72, 151462/720, 135388/730, and 135453/730; and the Natural Science and Engineering Research Council (NSERC), Canada, Discovery and Strategic grants. Any opinions, findings and conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. Address correspondence to Even H. Jørgensen, Norwegian Institute for Nature Research, The Polar Environmental Center, N-9296, Tormsø, Norway. E-mail: even.jorgensen@nfh.uit.no