Murray M J, Young M A, Santymire R M
Monterey Bay Aquarium, 886 Cannery Row, Monterey, CA 93940, USA.
Conservation & Science Department, Lincoln Park Zoo, 2001 N. Clark St., Chicago, IL 60614, USA.
Conserv Physiol. 2020 Feb 3;8(1):coz116. doi: 10.1093/conphys/coz116. eCollection 2020.
After nearly being hunted to extinction during the fur trade of the late 20th Century, sea otter () 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.
在20世纪后期的皮毛贸易中，海獭（）几近被捕杀至灭绝，如今其种群数量已在不同程度上恢复到历史分布范围。虽然总体种群数量和分布范围有所增加，但仍有一些地区的扩张速度较慢和/或动物数量减少，这可能是多种来源的慢性应激导致的。一些人通过糖皮质激素分析来验证这些解释。我们的目标是进行一项对照研究，利用人工饲养管理的海獭来验证血清糖皮质激素分析在监测海獭应激生理学方面的用途。我们使用标准促肾上腺皮质激素（ACTH）激发试验来比较皮质醇和皮质酮的反应，从而确定海獭体内的主要糖皮质激素。14只不同性别的海獭（5只雄性，9只雌性），包括幼年、亚成年和成年个体，参与了这项研究。测试结果支持皮质醇是海獭体内的主要糖皮质激素。性别和年龄并不影响个体对ACTH或生理盐水注射的反应。有趣的是，生理盐水注射不仅证实了ACTH对肾上腺糖皮质激素释放的影响，还提供了有关海獭在捕获和镇静后糖皮质激素水平恢复到基线所需时间的信息。从这项研究中获得的见解将有助于未来更好地理解应激在野生海獭种群中的作用。识别主要糖皮质激素将有助于评估更稳定的生物材料，如皮毛或胡须，这些材料受糖皮质激素昼夜循环的影响较小。
