Preliminary results of fasting on the kinetics of organochlorines in polar bears (Ursus maritimus)

Polischuk, Susan C.; Letcher, Robert J.; Norstrom, Ross J.; Ramsay, Malcolm A.

doi:10.1016/0048-9697(95)04380-j

Cited by 71 publications

(41 citation statements)

References 22 publications

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“…ΣPCBs did not differ between females with cubs of the year and single females, but was significantly lower in females with yearlings. Because the body mass of females with yearlings did not differ from that of the other reproductive groups, prolonged transfer of OCs from mothers to cubs through the lipid-rich milk may be the major cause of the lower levels in the females with yearlings (Addison and Brodie 1977;Oehme et al 1995;Polischuk 1999;Polischuk et al 1995). Reproductive history is thus probably one of the major factors affecting accumulation of PCBs in female polar bears, and females that rear cubs successfully may reduce their body burden of PCBs by excreting contaminants through milk at a greater rate than intake.…”

Section: Discussionmentioning

confidence: 99%

“…Females with 2-year-old offspring and single females were classified as single females (n = 32), because all these females enter estrus in spring and are thus available for mating (Wiig 1998). Because 2-year-old offspring receive very little milk (Polischuk et al 1995), and the fat content in milk declines as the cubs grow older (Derocher et al 1993), the transfer of PCBs to 2-year-olds through milk is presumed to be negligible. Females with nursing cubs less than 12 months of age were classed as females with cubs (n = 36), and those with dependent offspring 12-24 months of age were classed as females with yearlings (n = 18).…”

Section: Polychlorinated Biphenyls and Reproductive Hormones In Femalmentioning

confidence: 99%

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Polychlorinated biphenyls and reproductive hormones in female polar bears at Svalbard.

Haave

Ropstad

Derocher

et al. 2003

Environ Health Perspect

118

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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 (P 4 ) and 17β-estradiol (E 2 )] in free-living female polar bears from Svalbard. Concentrations of P 4 depended on reproductive status, and concentrations were lowest in females with offspring-females with cubs and females with yearlings. In these females, the P 4 concentrations were positively correlated with plasma ΣPCBs (sum of all analyzed polychlorinated biphenyl congeners) concentrations. The ΣPCBs concentrations explained 27% of the variation in the P 4 concentrations. There were no correlations between ΣPCBs and E 2 and cortisol in any of the groups of polar bears, or between ΣPCBs and P 4 in single polar bears. Although the ΣPCBs-P 4 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 P 4 in polar bear females. There is a clear need to further assess the hormone balance and population health of polar bears at Svalbard.

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Section: Discussionmentioning

confidence: 99%

Section: Polychlorinated Biphenyls and Reproductive Hormones In Femalmentioning

confidence: 99%

Polychlorinated biphenyls and reproductive hormones in female polar bears at Svalbard.

Haave

Ropstad

Derocher

et al. 2003

Environ Health Perspect

118

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“…Nowadays, environmental estrogens present a global distribution: high levels of dichlorodiphenyl-trichloroethane (DDT) have been found even in the arctic, remotely from industrialization [6,7]. Considering their ubiquitous nature, it is clear that human beings as well as domesticated and undomesticated animals are unavoidably exposed to these compounds.…”

Section: Environmental Estrogensmentioning

confidence: 99%

The role of environmental estrogens and autoimmunity

Chighizola

Meroni

2012

Autoimmunity Reviews

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“…Increases in tissue concentrations of some contaminants that are nearly proportional to the extent of fat reserve depletion have been documented in a number of species, including migrating fish, marine mammals, and hibernating polar bears (20)(21)(22)(23).…”

Section: Lipid Dynamics In Organismsmentioning

confidence: 99%

Peer Reviewed: Contaminant Amplification in the Environment

Macdonald¹,

Mackay²,

Hickie³

2002

Environ. Sci. Technol.

118

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An environmental chemist can quantify the presence of a hydrophobic organic contaminant at a 1 ng/L concentration in water. If a total mass of 10 ng of analyte is required, the obvious strategy is to obtain an adequate sample of the water, say 50 L, and increase the concentration by extracting it with an organic solvent, such as dichloromethane (DCM). If the extraction is completed with a total vol-BEVERLY DOYLE

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Preliminary results of fasting on the kinetics of organochlorines in polar bears (Ursus maritimus)

Cited by 71 publications

References 22 publications

Polychlorinated biphenyls and reproductive hormones in female polar bears at Svalbard.

Polychlorinated biphenyls and reproductive hormones in female polar bears at Svalbard.

The role of environmental estrogens and autoimmunity

Peer Reviewed: Contaminant Amplification in the Environment

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