(Table 1) Concentration of PCB and other contaminants in blood plasma of polar bears (Ursus maritimus) from Svalbard

• Main Authors: Gutleb, Arno C, Cenijn, Peter, van Velzen, Martin, Lie, Elisabeth, Ropstad, Erik, Skaare, Janneche Utne, Malmberg, Tina, Bergman, Åke, Gabrielsen, Geir W, Legler, Juliette
• Format: Dataset
• Language: English
• Published: PANGAEA 2010
• Subjects: 2,4,6-Tribromophenol; Age; comment; relative; number of years; alpha-Hexachlorocyclohexane; beta-Hexachlorocyclohexane; Biological sample; BIOS; Hexachlorobenzene; Hydroxylated polybrominated diphenyl ethers; Hydroxy-polychlorinated biphenyl 107; Hydroxy-polychlorinated biphenyl 146; Hydroxy-polychlorinated biphenyl 187; International Polar Year (2007-2008); IPY; Oxychlordane; para,para-Dichlorodiphenyldichloroethylene; Pentachlorophenol; Polychlorinated biphenyl 118; Polychlorinated biphenyl 128; Polychlorinated biphenyl 137; Polychlorinated biphenyl 138; Polychlorinated biphenyl 153; Polychlorinated biphenyl 156; Polychlorinated biphenyl 157; Polychlorinated biphenyl 170; Polychlorinated biphenyl 180; Polychlorinated biphenyl 183; Polychlorinated biphenyl 187; Polychlorinated biphenyl 189; Polychlorinated biphenyl 194; Polychlorinated biphenyl 206; Polychlorinated biphenyl 47; Polychlorinated biphenyl 99; Sex; Svalbard; Svalbard_bear; trans-Nonachlor; Ursus maritimus; International Polar Year
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.810387; https://doi.org/10.1594/PANGAEA.810387

Persistent chemicals accumulate in the arctic environment due to their chemical reactivity and physicochemical properties and polychlorinated biphenyls (PCBs) are the most concentrated pollutant class in polar bears (Ursus maritimus). Metabolism of PCB and polybrominated biphenyl ether (PBDE) flame-retardants alter their toxicological properties and these metabolites are known to interfere with the binding of thyroid hormone (TH) to transthyretin (TTR) in rodents and humans. In polar bear plasma samples no binding of [125I]-T4 to TTR was observed after incubation and PAGE separation. Incubation of the plasma samples with [14C]-4-OH-CB107, a compound with a higher binding affinity to TTR than the endogenous ligand T4 resulted in competitive binding as proven by the appearance of a radio labeled TTR peak in the gel. Plasma incubation with T4 up to 1 mM, a concentration that is not physiologically relevant anymore did not result in any visible competition. These results give evidence that the binding sites on TTR for T4 in wild living polar bears are completely saturated. Such saturation of binding sites can explain observed lowered levels of THs and could lead to contaminant transport into the developing fetus.