Hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (Ursus maritimus).
As a top predator in the Arctic food chain, polar bears (Ursus maritimus) are exposed to high levels of persistent organic pollutants (POPs). Because several of these compounds have been reported to alter endocrine pathways, such as the steroidogenesis, potential disruption of the sex steroid synthesis by POPs may cause implications for reproduction by interfering with ovulation, implantation and fertility. Blood samples were collected from 15 female polar bears in Svalbard (Norway) in April 2008. The concentrations of nine circulating steroid hormones; dehydroepiandrosterone (DHEA), androstenedione (AN), testosterone (TS), dihydrotestosterone (DHT), estrone (E1), 17α-estradiol (αE2), 17β-estradiol (βE2), pregnenolone (PRE) and progesterone (PRO) were determined. The aim of the study was to investigate associations among circulating levels of specific POP compounds and POP-metabolites (hydroxylated PCBs [OH-PCBs] and hydroxylated PBDEs [OH-PBDEs]), steroid hormones, biological and capture variables in female polar bears. Inverse correlations were found between circulating levels of PRE and AN, and circulating levels of OH-PCBs. There were no significant relationships between the steroid concentrations and other analyzed POPs or the variables capture date and capture location (latitude and longitude), lipid content, condition and body mass. Although statistical associations do not necessarily represent direct cause-effect relationships, the present study indicate that OH-PCBs may affect the circulating levels of AN and PRE in female polar bears and that OH-PCBs thus may interfere with the steroid homeostasis. Increase in PRO and a decrease in AN concentrations suggest that the enzyme CYP17 may be a potential target for OH-PCBs. In combination with natural stressors, ongoing climate change and contaminant exposure, it is possible that OH-PCBs may disturb the reproductive potential of polar bears.
Norwegian University of Science and Technology (NTNU), Department of Biology, Høgskoleringen 5, NO-7491 Trondheim, Norway.
Lisa
L
Gustavson
Norwegian University of Science and Technology (NTNU), Department of Biology, Høgskoleringen 5, NO-7491 Trondheim, Norway. Electronic address: tomasz.ciesielski@bio.ntnu.no.
Tomasz M
TM
Ciesielski
Norwegian University of Science and Technology (NTNU), Department of Biology, Høgskoleringen 5, NO-7491 Trondheim, Norway.
Jenny
J
Bytingsvik
University of Copenhagen, Toxicology Laboratory, Department of Pharmacy, Faculty of Health and Medical Sciences, Universitetsparken 2, 2100 Copenhagen, Denmark.
Bjarne
B
Styrishave
University of Copenhagen, Toxicology Laboratory, Department of Pharmacy, Faculty of Health and Medical Sciences, Universitetsparken 2, 2100 Copenhagen, Denmark.
Martin
M
Hansen
The Norwegian School of Veterinary Science (NVH), Department of Food Safety and Infection Biology, P.O. Box 5003, Campus Adamstuen, NO-1432 Ås, Norway.
Elisabeth
E
Lie
Norwegian Polar Institute (NPI), Fram Centre, NO-9296 Tromsø, Norway.
Jon
J
Aars
Norwegian University of Science and Technology (NTNU), Department of Biology, Høgskoleringen 5, NO-7491 Trondheim, Norway.
Bjørn M
BM
Jenssen
D000818:Animals; D052244:Endocrine Disruptors / Q000097:blood*; D004781:Environmental Exposure; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000097:blood / Q000633:toxicity*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D012739:Gonadal Steroid Hormones / Q000097:blood*; D055768:Halogenated Diphenyl Ethers / Q000097:blood; D009664:Norway; D010575:Pesticides / Q000097:blood / Q000494:pharmacology / Q000633:toxicity; D011078:Polychlorinated Biphenyls / Q000097:blood / Q000633:toxicity*; D053719:Tandem Mass Spectrometry; D001503:Ursidae / Q000378:metabolism*
D052244:Endocrine Disruptors; D004785:Environmental Pollutants; D012739:Gonadal Steroid Hormones; D055768:Halogenated Diphenyl Ethers; D010575:Pesticides; D011078:Polychlorinated Biphenyls
POPs; Polar bears; Steroid hormones