After nearly being hunted to extinction during the fur trade of the late 20th Century, sea otter (Enhydra lutris) populations have recovered to varying degrees of their historical range. While overall population numbers and range have increased, there are regions in which expansion has occurred at a slower rate and/or animal numbers have decreased, which may be a result of chronic stress from a variety of sources. Some have employed glucocorticoid analysis in their attempts to validate these explanations. Our goal was to conduct a controlled study using sea otters managed under human care to validate the use of serum glucocorticoid analysis to monitor stress physiology in the sea otter. We used a standard ACTH challenge test to compare cortisol and corticosterone responses, thereby identifying the primary glucocorticoid in the sea otter. Fourteen sea otters of both sexes (five males, nine females), including juveniles, sub-adults and adults, participated in the study. The results of the testing supported cortisol as the primary glucocorticoid in the sea otter. Sex and age did not affect how the individual responded to the ACTH or saline injection. Interestingly, the saline injection not only confirmed the effects of the ACTH on glucocorticoid release from the adrenal glands but also provided information on how long it takes the sea otter's glucocorticoid levels to return to baseline after capture and sedation. The insight gained from this study will aid in future efforts to better understand the role of stress in free-ranging sea otter populations. Recognition of the primary glucocorticoid will facilitate evaluation of more stable biological material, such as fur or whiskers, which tend to be less affected by the diurnal cycling of glucocorticoids.

中文翻译：

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使用ACTH激发试验鉴定南部水獭（Enhydra lutris nereis）中主要的糖皮质激素。

在20世纪后期的毛皮贸易中几乎被捕猎而灭绝后，海獭（Enhydra lutris）的种群已恢复到其历史范围的不同程度。虽然总体种群数量和范围增加了，但有些地区的扩张速度较慢和/或动物数量减少了，这可能是来自各种来源的长期压力造成的。一些人尝试使用糖皮质激素分析来验证这些解释。我们的目标是使用在人类照料下管理的海獭进行一项对照研究，以验证使用血清糖皮质激素分析来监测海獭的应激生理。我们使用标准的ACTH激发试验来比较皮质醇和皮质酮的反应，从而确定海獭中的主要糖皮质激素。包括少年，亚成年和成人在内的十四个男女的水獭（五男，九女）参加了这项研究。测试结果支持皮质醇作为海獭中的主要糖皮质激素。性别和年龄不影响个体对ACTH或生理盐水注射的反应。有趣的是，盐水注射不仅证实了ACTH对肾上腺糖皮质激素释放的影响，而且还提供了有关海獭的糖皮质激素水平在捕获和镇静后需要多长时间才能恢复到基线的信息。从这项研究中获得的见识将有助于未来的工作，以更好地了解压力在自由放养的水獭种群中的作用。对主要糖皮质激素的识别将有助于评估更稳定的生物材料，例如毛皮或胡须，