Per- and polyfluoroalkyl substances (PFASs) - New endocrine disruptors in polar bears (Ursus maritimus)?

• Published in: Environment International
• Main Authors: Pedersen, Kathrine Eggers, Letcher, Robert J, Sonne, Christian, Dietz, Rune, Styrishave, Bjarne
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Arctic; East Greenland; Greenland; Ursus maritimus
• Online Access: https://curis.ku.dk/portal/da/publications/per-and-polyfluoroalkyl-substances-pfass--new-endocrine-disruptors-in-polar-bears-ursus-maritimus(3c240a8c-5238-438a-b7b3-a2a96579e6ef).html; https://doi.org/10.1016/j.envint.2016.07.015

Per- and polyfluoroalkyl substances (PFASs) are emerging in the Arctic and accumulate in brain tissues of East Greenland (EG) polar bears. In vitro studies have shown that PFASs might possess endocrine disrupting abilities and therefore the present study was conducted to investigate potential PFAS induced alterations in brain steroid concentrations. The concentrations of eleven steroid hormones were determined in eight brain regions from ten EG polar bears. Pregnenolone (PRE), the dominant progestagen, was found in mean concentrations of 5-47ng/g (ww) depending on brain region. PRE showed significantly (p<0.01) higher concentrations in female compared to male bears. Dehydroepiandrosterone (DHEA) found in mean concentrations 0.67-4.58ng/g (ww) was the androgen found in highest concentrations. Among the estrogens estrone (E1) showed mean concentrations of 0.90-2.21ng/g (ww) and was the most abundant. Remaining steroid hormones were generally present in concentrations below 2ng/g (ww). Steroid levels in brain tissue could not be explained by steroid levels in plasma. There was however a trend towards increasing estrogen levels in plasma resulting in increasing levels of androgens in brain tissue. Correlative analyses showed positive associations between PFASs and 17α-hydroxypregnenolone (OH-PRE) (e.g. perflouroalkyl sulfonates (∑PFSA): p<0.01, r=0.39; perfluoroalkyl carboxylates (∑PFCA): p<0.01, r=0.61) and PFCA and testosterone (TS) (∑PFCA: p=0.03, r=0.30) across brain regions. Further when investigating correlative associations in specific brain regions significant positive correlations were found between ∑PFCA and several steroid hormones in the occipital lobe. Correlative positive associations between PFCAs and steroids were especially observed for PRE, progesterone (PRO), OH-PRE, DHEA, androstenedione (AN) and testosterone (TS) (all p≤0.01, r≥0.7). The results from the present study generally indicate that an increase in PFASs concentration seems to concur with an increase in steroid hormones of EG ...