Dear all - perhaps of most interest to those of you working with endocrine disrupting contaminants, my colleagues and I recently published a new study on the relationship between mercury (MeHg) and cortisol. Although mercury has been found to have endocrine disrupting properties in other species, exceedingly few such studies have been done on mammals.For a pdf copy, please either contact me or follow the link: http://link.springer.com/article/10.1007%2Fs10646-015-1506-9 Best, Thea
Reference Bechshoft T, Derocher AE, Richardson E, Mislan P, Lunn NJ, Sonne C, Dietz R, Janz DM, St. Louis VL. 2015. Mercury and cortisol in Western Hudson Bay polar bear hair. Ecotoxicology, DOI: 10.1007/s10646-015-1506-9 Abstract Non-invasive methods of assessing animal health and life history are becoming increasingly popular in wildlife research; hair samples from polar bears (Ursus maritimus), are being used to study an ever broader range of anthropogenic and endocrine compounds. A number of contaminants are known to disrupt endocrine function in polar bears. However, the relationship between mercury and cortisol remains unknown, although mercury is an endocrine disruptor in other species. Here, we examine the relationship between concentrations of cortisol and total mercury (THg) analyzed in guard hair from 378 polar bears (184 females, 194 males) sampled in Western Hudson Bay, 2004-2012. The difference in mean cortisol concentration between female (0.8 ± 0.6 pg/mg) and male (0.7 ± 0.5 pg/mg) polar bears bordered on significance (p = 0.054). However, mean mercury concentration was significantly greater (p = 0.009) in females (4.7 ± 1.4 μg/g) than males (4.3 ± 1.2 μg/g). Hair cortisol in males was significantly influenced by mercury, age, and fatness, as well as interactions between mercury and year, mercury and fatness, and year and fatness (all: p < 0.03) (multiple regression analysis, whole model: r2 = 0.14, F7,185 = 4.43, p = 0.0001). Fatness was the only significant variable in the multiple regression analysis for females (r2 = 0.06, F1,182 = 13.0, p = 0.0004). In conclusion, a significant, but complex, relationship was found between mercury and cortisol concentrations in hair from male, but not female, polar bears.
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