title: Biomarker response and hypothalamus-pituitary-interrenal axis functioning in Arctic charr from Bjørnøya (74°30' N), Norway, with high levels of organohalogenated compounds.
abstract: The populations of Arctic charr (Salvelinus alpinus) residing in Lake Ellasjøen at Bjørnøya Island in the Norwegian Arctic (74° 30'N, 19° 00'E) possess substantially higher levels of organohalogenated compounds (strongly dominated by polychlorinated biphenyls, PCBs) than conspecifics residing in other, proximate lakes on the island. In the present study we sampled large (<400g), immature charr from Lake Ellasjøen (high PCB levels) and Lake Laksvatn (reference lake, low PCB levels) by hook and line for an immediate blood sampling, and blood and tissue sampling after a 1h confinement stressor. This was done in order to investigate possible effects of pollutants on an acute stress performance in a high-latitude fish species by comparing muscle PCB levels, hepatic cytochrome P4501A (CYP1A) biomarker activation and functioning of the hypothalamus-pituitary-interrenal (HPI) axis between these two populations of Arctic charr. As expected sum PCB muscle levels were 8-fold higher on a wet weigh basis, and 19-fold higher on a lipid weight basis, in charr from Ellasjøen than in charr from Laksvatn. This was accompanied by a 3.5-fold higher liver cyp1a mRNA abundance in the Ellasjøen charr compared to Laksvatn charr. Brain transcript levels encoding glucocorticoid receptor 1 and 2 (GR2) and corticotropin-releasing factor, and pituitary transcript levels encoding GR2 and proopiomelanocortin A1 and A2 were higher in Ellasjøen charr than in Laksvatn charr, while interrenal transcript levels encoding melanocortin 2 receptor and steroidogenic acute regulatory protein were lower. There were no differences in plasma cortisol concentration between the two charr populations immediately after capture and one hour after confinement. The strong biomarker response to OHCs and altered mRNA abundances of key genes related to HPI axis functioning in the Ellasjøen charr suggest endocrine disruptive effects of OHCs in this charr population. Possible ecological implications are not known, but it cannot be excluded that a slower growth rate in Ellasjøen charr compared to Laksvatn charr due to an increased metabolic demand associated with the activation of xenobiotic defense and detoxification systems may have contributed to the lower body mass of Ellasjøen charr compared to Laksvatn charr.
authors.affiliation: Department of Arctic and Marine Biology, UiT the Arctic University of Norway, NO-9037, Tormsø, Norway. Electronic address: even.jorgensen@uit.no.
authors.forename: Even H
authors.initials: EH
authors.lastname: Jørgensen
authors.affiliation: United States Geological Survey (Retired), 441 Ashley Dr. Underwood, WA 98651, USA. Electronic address: agmaule@gmail.com.
authors.forename: Alec G
authors.initials: AG
authors.lastname: Maule
authors.affiliation: Department of Arctic and Marine Biology, UiT the Arctic University of Norway, NO-9037, Tormsø, Norway; Akvaplan-niva AS, Fram Centre-High North Research Centre for Climate and the Environment, Hjalmar Johansens Gate 14, 9007 Tromsø, Norway. Electronic address: anita.evenset@akvaplan.niva.no.
authors.forename: Anita
authors.initials: A
authors.lastname: Evenset
authors.affiliation: Akvaplan-niva AS, Fram Centre-High North Research Centre for Climate and the Environment, Hjalmar Johansens Gate 14, 9007 Tromsø, Norway. Electronic address: guttorm.christensen@akvaplan.niva.no.
authors.forename: Guttorm
authors.initials: G
authors.lastname: Christensen
authors.affiliation: Akvaplan-niva AS, Fram Centre-High North Research Centre for Climate and the Environment, Hjalmar Johansens Gate 14, 9007 Tromsø, Norway. Electronic address: jenny.bytingsvik@akvaplan.niva.no.
authors.forename: Jenny
authors.initials: J
authors.lastname: Bytningsvik
authors.affiliation: Akvaplan-niva AS, Fram Centre-High North Research Centre for Climate and the Environment, Hjalmar Johansens Gate 14, 9007 Tromsø, Norway. Electronic address: marianne.frantzen@akvaplan.niva.no.
authors.forename: Marianne
authors.initials: M
authors.lastname: Frantzen
authors.affiliation: Norwegian Institute for Air Research, Fram Centre-High North Research Centre for Climate and the Environment, Hjalmar Johansens Gate 14, 9007 Tromsø, Norway. Electronic address: valdimir.nikiforov@nilu.no.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Nikiforov
authors.affiliation: Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N1N4, Canada. Electronic address: erinfaught@gmail.com.
authors.forename: Erin
authors.initials: E
authors.lastname: Faught
authors.affiliation: Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N1N4, Canada. Electronic address: mmvijaya@ucalgary.ca.
authors.forename: Mathilakath M
authors.initials: MM
authors.lastname: Vijayan
mesh_terms: D000818:Animals; D001110:Arctic Regions; D015415:Biomarkers / Q000097:blood; D003346:Corticotropin-Releasing Hormone / Q000097:blood; D052244:Endocrine Disruptors / Q000493:pharmacokinetics / Q000633:toxicity*; D004784:Environmental Monitoring; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000378:metabolism; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D060106:Lakes / Q000737:chemistry; D009664:Norway; D011078:Polychlorinated Biphenyls / Q000493:pharmacokinetics / Q000633:toxicity*; D014018:Tissue Distribution; D014337:Trout / Q000097:blood* / Q000378:metabolism / Q000502:physiology; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D052244:Endocrine Disruptors; D014874:Water Pollutants, Chemical; D003346:Corticotropin-Releasing Hormone; D011078:Polychlorinated Biphenyls; D006854:Hydrocortisone
keywords: Arctic; Cortisol; Polychlorinated biphenyls; Salvelinus alpinus; StAR; Stress; Svalbard