J�RGENSEN, E.H.*; BURKOW, I.C.; ANDERSSON, P.; JOBLING, M.; Norwegian Institute for Nature Research, Troms�, Norway; Norwegain institute for Fisheries and Aquaculture, Troms�, Norway; Ume� University, Ume�, Sweden; University of Troms�, Troms�, Norway: Winter emaciation potentiate responses to organochlorine pollutants in Arctic charr

In the present study the toxicokinetics of polychlorinated biphenyls (PCBs) and associated hepatic P450 (CYP)1A responses were studied in wild migratory Arctic charr (Salvelinus alpinus) during winter emaciation. The fish were captured as they returned from their summer feeding residence in seawater and transferred to indoor tank facilities. There they were held throughout winter at natural temperature and light conditions. The fish were not fed during this time to mimic the natural feeding habit of this species. In September the fish were given a single, oral dose of either 0 (control), 0.1, 1 or 50 �g PCB/gram fish. During winter there was a net loss of PCB from the carcass, whereas there were net inputs, and increases in concentrations of PCB in the liver (up to 3-fold) and brain (up to 10-fold). In October, hepatic CYP1A activities was low in the groups given 0, 0.1 and 1 �g PCB/gram fish, and very high in the group given 50 �g PCB/gram fish. During winter there was seen a 12-fold increase in CYP1A activity in the fish that had been given 1 �g PCB/gram fish, despite a 20% reduction in their total body burden of PCB. In May the CYP1A activities of these fish were similar to those recorded in the fish that had been given 50 �g PCB/gram fish. These results demonstrate that long-term fasting and lipid mobilization may have a dramatic effect on the biological activity of lipophilic organochlorines and corresponding biomarker responses. Overall, the findings point to potentiated risks of biological effects of OCs during periods of emaciation and indicates that high latitude animals may be extra sensitive to these pollutants.