Vitamins A and E in liver, kidney, and whole blood of East Greenland polar bears sampled 1994–2008: reference values and temporal trends
- 228 Downloads
Vitamins A (retinol) and E (α-tocopherol) are dietary vitamins, essential for, e.g., growth and development, reproduction, and immune function. Persistent organic pollutants (POPs) have been found to be related to vitamin A and E metabolism. However, few investigations have been published on this health issue in polar bears (Ursus maritimus). The aim of this study was thus to provide reference values for concentrations of vitamin A in liver, kidney cortex, and whole blood and vitamin E in kidney cortex and whole blood from 166 East Greenland polar bears, as well as to assess the relationship between POPs and vitamin concentrations. In addition, vitamin concentrations were analyzed for temporal trends (1994–2008). Results showed vitamin A in liver to be higher in adult bears and the concentrations of vitamin E in kidney and blood to likewise be generally higher in adult bears. In addition, all analyzed contaminant groups were correlated with at least one of the vitamin parameters, predominantly in a negative way. Finally, vitamin A liver concentrations as well as concentration of vitamin E in kidney and blood showed a temporal increase. Together, these results add to the weight of evidence that POPs could be disrupting polar bear vitamin status. However, while the observed temporal increases in vitamin concentrations were likely POP related, the question remains as to whether they stem from influence of contaminants only or also, e.g., changes in prey species. Further studies are needed to tease apart the causes underlying these changes in vitamin concentrations.
KeywordsPolar bear Ursus maritimus Retinol α-Tocopherol Persistent organic pollutant (POP) Temporal trend
Jonas Brønlund and local hunters are acknowledged for organizing the sampling in East Greenland. Financial support was provided by the Prince Albert II of Monaco Foundation, the Danish Cooperation for Environment in the Arctic (DANCEA), and the Commission for Scientific Research in Greenland.
Compliance with ethical standards
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.
- Bechshøft TØ, Rigét FF, Sonne C, Letcher RJ, Muir DCG, Novak MA, Henchey E, Meyer JS, Eulaers I, Jaspers V, Eens M, Covaci A, Dietz R (2012) Measuring environmental stress in East Greenland polar bears, 1892–1927 and 1988–2009: what does hair cortisol tell us? Environ Int 45:15–21CrossRefPubMedGoogle Scholar
- BS EN12822 (2000a) Foodstuffs. Determination of vitamin E by high performance liquid chromatography. Measurement of α-, β-, γ- and δ-tocopherol. ISO Central Secretariat, GenevaGoogle Scholar
- BS EN12823-1 (2000b) Foodstuffs. Determination of vitamin A by high performance liquid chromatography. Measurement of all-trans-retinol and 13-cis-retinol. ISO Central Secretariat, GenevaGoogle Scholar
- BS EN ISO/IEC (2005) ISO/IEC 17025:2005. General requirements for the competence of testing and calibration laboratories. ISO Central Secretariat, GenevaGoogle Scholar
- Calvert W, Ramsay MA (1998) Evaluation of age determination of polar bears by counts of cementum growth layer groups. Ursus 10:449–453Google Scholar
- Gutleb A, Cenijn P, van Velzen M, Lie E, Ropstad E, Skaare JU, Malmberg T, Bergman Å, Gabrielsen GW, Legler J (2010) In vitro assay shows that PCB metabolites completely saturate thyroid hormone transport capacity in blood of wild Polar bears (Ursus maritimus). Environ Sci Technol 44:3149–3154CrossRefPubMedGoogle Scholar
- Hair JF, Black WC, Babin BJ, Andereson RE, Tatham RL (2006) Multivariate data analysis. Pearson Education, Upper Saddle RiverGoogle Scholar
- Rosing-Asvid A, Born EW, Kingsley MCS (2002) Age at sexual maturity of males and timing of the mating season of polar bears (Ursus maritimus) in Greenland. Polar Biol 25:878–883Google Scholar
- Sandau CD (2000) Analytical chemistry of hydroxylated metabolites of PCBs and other halogenated phenolic compounds in blood and their relationship to thyroid hormone and retinol homeostasis in humans and polar bears. Dissertation, Carleton UniversityGoogle Scholar
- Sandell HT, Sandell B, Born EW, Dietz R, Sonne-Hansen C (2001) Isbjørne i Østgrønland. En interviewundersøgelse om forekomst og fangst (Polar bears in East Greenland: An interview survey about occurrence and the hunt). Teknisk rapport nr. 40. Pinngortitaleriffik, Grønlands Naturinstitut, Nuuk. 94 pp (in Danish with an English summary)Google Scholar
- Simon E, van Velzen M, Brandsma SH, Lie E, Loken K, de Boer J, Bytingsvik J, Jenssen BM, Aars J, Hamers T, Lamoree MH (2013) Effect-directed analysis to explore the polar bear exposome: identification of thyroid hormone disrupting compounds in plasma. Environ Sci Technol 47:8902–8912CrossRefPubMedGoogle Scholar
- Villanger GD, Jenssen BM, Fjeldberg RR, Letcher RJ, Muir DCG, Kirkegaard M, Sonne C, Dietz R (2011) Exposure to mixtures of organohalogen contaminants and associative interactions with thyroid hormones in East Greenland polar bears (Ursus maritimus). Environ Int 37:694–708CrossRefPubMedGoogle Scholar