Adrenocortical response to stress and thyroid hormone status in free-living nestling white storks (Ciconia ciconia) exposed to heavy metal and arsenic contamination.
Adrenocortical response to stress and thyroid hormone status in free-living nestling white storks (Ciconia ciconia) exposed to heavy metal and arsenic contamination.
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DOI：
10.1289/ehp.9099
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发表时间：
2006-10
影响因子：
10.4
通讯作者：
Hiraldo, Fernando
中科院分区：
文献类型：
--
作者：
Baos, Raquel;Blas, Julio;Bortolotti, Gary R;Marchant, Tracy A;Hiraldo, Fernando
内分泌参数在检测对污染物的早期或低水平反应方面已被证明是有用的。虽然大多数关于内分泌调节的研究都集中在涉及性腺类固醇的过程上，但污染物也可能针对内分泌系统的其他部分。在本研究中，我们检测了自由生活雏鸟白鹳（Ciconia Ciconia）肾上腺皮质应激反应和甲状腺激素水平与血液中重金属（锌、铅、铜、镉）和砷水平的关系。实地调查是在Aznalcóllar矿事故污染地区（西班牙西南部）和一个参考地点进行的。我们使用标准化的捕获、处理和约束方案来确定基线和最大血浆皮质酮。同时测定甲状腺素（T4）和三碘甲状腺原氨酸（T3）的循环水平。没有发现金属或砷对基线皮质酮的影响，但皮质酮的最高水平在两个地点与铅呈正相关。这种关系在单个雏鸟中比在多个雏鸟中更强，这表明铅对压力更大的个体的影响更大。金属污染不影响血浆T4或T3水平，但甲状腺状态随部位不同而不同。由于下丘脑-垂体-肾上腺（HPA）功能受损会对生存所必需的行为和代谢过程的改变产生深远的影响，我们的研究结果表明，暴露于亚致死铅水平的鸟类可能通过改变肾上腺皮质应激反应而处于危险之中，并进一步支持HPA轴相关终点可能是野生动物金属暴露和潜在毒性的有用指标的观点。
Endocrine parameters have proven useful in the detection of early or low-level responses to pollutants. Although most of the studies on endocrine modulation have been focused on processes involving gonadal steroids, contaminants may target other parts of the endocrine system as well. In this study we examined the adrenocortical stress response and thyroid hormone status in free-living nestling white storks (Ciconia ciconia) in relation to heavy metals (zinc, lead, copper, cadmium) and arsenic levels in blood. Fieldwork was conducted in an area polluted by the Aznalcóllar mine accident (southwestern Spain) and in a reference site. We used a standardized capture, handling, and restraint protocol to determine both baseline and maximum plasma corticosterone. Circulating levels of thyroxine (T4) and triiodothyronine (T3) were also measured. No effects of metals or As were found on baseline corticosterone, but maximum levels of corticosterone were positively related to Pb in both locations. This relationship was stronger in single nestlings than in birds from multiple-chick broods, which suggests a greater impact of Pb on more stressed individuals. Metal pollution did not affect plasma T4 or T3 levels, although thyroid status differed with location. Because a compromised hypothalamus–pituitary–adrenal (HPA) function can have far-reaching consequences in terms of altered behavioral and metabolic processes necessary for survival, our results suggest that birds exposed to sublethal Pb levels may be at risk through an altered adrenocortical stress response, and further support the idea that HPA axis-related end points might be useful indicators of metal exposure and potential toxicity in wild animals.