Maddux Sarah L, Cristol Daniel A, Varian-Ramos Claire W, Bradley Eric L
Department of Biology, College of William and Mary, Williamsburg, VA, 23187, USA.
Bull Environ Contam Toxicol. 2015 Feb;94(2):135-9. doi: 10.1007/s00128-014-1440-1. Epub 2014 Dec 21.
Although songbirds accumulate mercury at rates equivalent to better-studied aquatic avian species, effects of mercury bioaccumulation in songbirds remain understudied. Little is known about the effects of mercury on endocrine physiology, but recent evidence indicates that mercury may disrupt the function of the hypothalamic-pituitary-adrenal axis. Both field-based correlational studies and a recent dosing experiment suggest that mercury exposure alters levels of the primary avian stress hormone, CORT. We sampled zebra finches that had been dosed with 0, 0.5, or 1.0 ppm dietary methylmercury for baseline CORT twice; once during pairing and once after successfully fledging young. Circulating levels of CORT were not significantly affected by mercury exposure. However, our findings indicate potentially important differences in CORT responses between the sexes when exposed to environmentally relevant doses of mercury across the nesting cycle.
尽管鸣禽积累汞的速度与研究更充分的水生鸟类相当，但汞在鸣禽体内生物积累的影响仍未得到充分研究。关于汞对内分泌生理学的影响知之甚少，但最近的证据表明，汞可能会扰乱下丘脑 - 垂体 - 肾上腺轴的功能。基于野外的相关性研究和最近的剂量实验都表明，接触汞会改变鸟类主要应激激素CORT的水平。我们对分别摄入0、0.5或1.0 ppm膳食甲基汞的斑胸草雀进行了两次采样，以获取其基础CORT水平；一次在配对期间，一次在成功育雏后。汞暴露对CORT的循环水平没有显著影响。然而，我们的研究结果表明，在整个筑巢周期中，当接触环境相关剂量的汞时，两性之间的CORT反应可能存在重要差异。
