Hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (Ursus maritimus)

Lisa Gustavson; Tomasz M Ciesielski; Jenny Bytingsvik; Bjarne Styrishave; Martin Hansen; Elisabeth Lie; Jon Aars; Bjørn M Jenssen

doi:10.1016/j.envres.2015.02.011

Hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (Ursus maritimus)

Lisa Gustavson, Tomasz M Ciesielski, Jenny Bytingsvik, Bjarne Styrishave, Martin Hansen, Elisabeth Lie, Jon Aars, Bjørn M Jenssen

34 Citations (Scopus)

Abstract

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. •We analyzed concentrations of POPs and steroid hormones in blood of female polar bears.•Inverse relationships were found between levels of PRE and AN, and OH-PCBs.•Combined with other stressors OH-PCBs may disturb reproductive potential of polar bears.

Original language	English
Journal	Environmental Research
Volume	138
Pages (from-to)	191-201
Number of pages	11
ISSN	0013-9351
DOIs	https://doi.org/10.1016/j.envres.2015.02.011
Publication status	Published - 1 Apr 2015

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10.1016/j.envres.2015.02.011

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title = "Hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (Ursus maritimus)",

abstract = "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. •We analyzed concentrations of POPs and steroid hormones in blood of female polar bears.•Inverse relationships were found between levels of PRE and AN, and OH-PCBs.•Combined with other stressors OH-PCBs may disturb reproductive potential of polar bears.",

author = "Lisa Gustavson and Ciesielski, {Tomasz M} and Jenny Bytingsvik and Bjarne Styrishave and Martin Hansen and Elisabeth Lie and Jon Aars and Jenssen, {Bj{\o}rn M}",

year = "2015",

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doi = "10.1016/j.envres.2015.02.011",

language = "English",

volume = "138",

pages = "191--201",

journal = "Environmental Research",

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T1 - Hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (Ursus maritimus)

AU - Gustavson, Lisa

AU - Ciesielski, Tomasz M

AU - Bytingsvik, Jenny

AU - Styrishave, Bjarne

AU - Hansen, Martin

AU - Lie, Elisabeth

AU - Aars, Jon

AU - Jenssen, Bjørn M

PY - 2015/4/1

Y1 - 2015/4/1

N2 - 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. •We analyzed concentrations of POPs and steroid hormones in blood of female polar bears.•Inverse relationships were found between levels of PRE and AN, and OH-PCBs.•Combined with other stressors OH-PCBs may disturb reproductive potential of polar bears.

AB - 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. •We analyzed concentrations of POPs and steroid hormones in blood of female polar bears.•Inverse relationships were found between levels of PRE and AN, and OH-PCBs.•Combined with other stressors OH-PCBs may disturb reproductive potential of polar bears.

U2 - 10.1016/j.envres.2015.02.011

DO - 10.1016/j.envres.2015.02.011

M3 - Journal article

C2 - 25725300

SN - 0013-9351

VL - 138

SP - 191

EP - 201

JO - Environmental Research

JF - Environmental Research

ER -

Hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (Ursus maritimus)

Abstract

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