title: Contrasting retinoid and thyroid hormone status in differentially-contaminated northern fulmar colonies from the Canadian Arctic, Svalbard and the Faroe Islands.
abstract: The northern fulmar (Fulmarus glacialis) has previously been shown to accumulate a wide range, and occasionally high concentrations of organochlorines (OCs) (e.g., PCBs, chlorobenzenes, DDT- and chlordane-related compounds, dioxins and furans). The present study aimed to investigate, using a meta-analysis approach, the variations in cytochrome P450 (CYP) 1A-like enzyme induction based on ethoxyresorufin O-deethylase activity (EROD) and selected physiological variables (retinoids and thyroid hormones) in northern fulmar breeding in three differentially OC-exposed populations: Nunavut (Canadian Arctic), Svalbard (Norwegian Arctic) and the Faroe Islands. Substantially higher (roughly two-fold) OC levels were uncovered in the liver of this long-lived fulmarine petrel breeding in the Faroe Islands relative to Svalbard and Nunavut. Liver levels of PCDDs, PCDFs and non-ortho PCBs in Faroe Islands fulmars were amongst the highest reported thus far in any seabirds from the northern regions. Positive correlations were depicted in combined fulmars (all three populations) between hepatic EROD activity and concentrations of OCs, in which strongest associations were found for dioxin-like compound (PCDFs and PCDDs) and TEQ concentrations. Moreover, moderate to strong positive correlations were found between liver OC concentrations and plasma total thyroxin (TT(4)) levels and TT(4)/total triiodothyronine (TT(3)) level ratios, as well as strong negative correlations between the same suite of OCs and plasma TT(3) levels. Hepatic OC concentrations (PCBs, PCDDs, PCDFs, HCB, p,p'-DDE and oxychlordane) also were positively correlated with hepatic retinyl palmitate levels which, in turn, were associated with a significant decrease in plasma retinol levels and somewhat unchanged liver retinol levels. The present meta-analysis investigation on northern fulmar breeding in three geographically-distant sites illustrated that OC exposure (mainly PCBs and dioxins/furans) may be associated with modulation of the thyroid and retinoid homeostasis. However, the impact of confounding environmental factors (e.g., temperature and nutritional status) on current physiological variable variations could not be ruled out, and thus any cause-effect linkages between thyroid and retinoid system perturbation and OC exposure cannot be ascertained.
authors.affiliation: Centre de recherche en toxicologie de l'environnement (TOXEN), Département des sciences biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montréal, Québec, Canada. verreault.jonathan@uqam.ca
authors.forename: Jonathan
authors.initials: J
authors.lastname: Verreault
authors.forename: Lisa B
authors.initials: LB
authors.lastname: Helgason
authors.forename: Geir W
authors.initials: GW
authors.lastname: Gabrielsen
authors.forename: Maria
authors.initials: M
authors.lastname: Dam
authors.forename: Birgit M
authors.initials: BM
authors.lastname: Braune
mesh_terms: D000818:Animals; D001110:Arctic Regions; D001572:Benzofurans / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D001717:Birds / Q000378:metabolism*; D002170:Canada; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D003718:Denmark; D000072338:Dibenzofurans, Polychlorinated; D003633:Dichlorodiphenyl Dichloroethylene / Q000378:metabolism; D004224:Diterpenes; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000378:metabolism; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D020957:Nunavut; D011078:Polychlorinated Biphenyls / Q000032:analysis; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives / Q000378:metabolism; D012176:Retinoids / Q000378:metabolism*; D000084562:Retinyl Esters; D013538:Svalbard; D013961:Thyroid Gland / Q000737:chemistry; D013963:Thyroid Hormones / Q000378:metabolism*; D014801:Vitamin A / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D001572:Benzofurans; D015415:Biomarkers; D000072338:Dibenzofurans, Polychlorinated; D004224:Diterpenes; D004785:Environmental Pollutants; D006843:Hydrocarbons, Chlorinated; D000072317:Polychlorinated Dibenzodioxins; D012176:Retinoids; D000084562:Retinyl Esters; D013963:Thyroid Hormones; D014801:Vitamin A; C014794:retinol palmitate; D003633:Dichlorodiphenyl Dichloroethylene; D011078:Polychlorinated Biphenyls; D019363:Cytochrome P-450 CYP1A1