title: Polychlorinated biphenyls and reproductive hormones in female polar bears at Svalbard.
abstract: High concentrations of polychlorinated biphenyls (PCBs) in polar bears from Svalbard have increased concern for that population's reproductive health. We examined whether there were associations between the plasma concentrations of PCBs and reproductive hormones [progesterone (P4)] and 17 beta-estradiol (E2)] in free-living female polar bears from Svalbard. Concentrations of P4 depended on reproductive status, and concentrations were lowest in females with offspring--females with cubs and females with yearlings. In these females, the P4 concentrations were positively correlated with plasma sigma PCBs (sum of all analyzed polychlorinated biphenyl congeners) concentrations. The sigma PCBs concentrations explained 27% of the variation in the P4 concentrations. There were no correlations between sigma PCBs and E2 and cortisol in any of the groups of polar bears, or between sigma PCBs and P4 in single polar bears. Although the sigma PCBs-P4 relationship in female polar bears with offspring is not evidence per se of a direct cause-effect association, the results indicate that PCBs may affect levels of P4 in polar bear females. There is a clear need to further assess the hormone balance and population health of polar bears at Svalbard.
authors.affiliation: Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Marte
authors.initials: M
authors.lastname: Haave
authors.forename: Erik
authors.initials: E
authors.lastname: Ropstad
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Derocher
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lie
authors.forename: Ellen
authors.initials: E
authors.lastname: Dahl
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Wiig
authors.forename: Janneche U
authors.initials: JU
authors.lastname: Skaare
authors.forename: Bjørn Munro
authors.initials: BM
authors.lastname: Jenssen
mesh_terms: D000818:Animals; D001110:Arctic Regions; D004305:Dose-Response Relationship, Drug; D004703:Endocrine System / Q000187:drug effects; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000009:adverse effects* / Q000097:blood*; D004958:Estradiol / Q000097:blood*; D005260:Female; D006304:Health Status; D009664:Norway; D011078:Polychlorinated Biphenyls / Q000009:adverse effects* / Q000097:blood*; D011374:Progesterone / Q000097:blood*; D012098:Reproduction; D001503:Ursidae / Q000502:physiology*
chemical_list: D004785:Environmental Pollutants; D011374:Progesterone; D004958:Estradiol; D011078:Polychlorinated Biphenyls