Woodruff Julie A, Lacey Eileen A, Bentley George
Museum of Vertebrate Zoology, University of California, Berkeley, California, USA.
J Exp Zool A Ecol Genet Physiol. 2010 Oct 1;313(8):498-507. doi: 10.1002/jez.621.
The environment in which an animal lives can profoundly influence its biology, including physiological responses to external stressors. To examine the effects of environmental conditions on physiological stress reactions in colonial tuco-tucos (Ctenomys sociabilis), we measured glucocorticoid (GC) levels in captive and free-living members of this species of social, subterranean rodent. Analyses of plasma and fecal samples revealed immunoreactive corticosterone (metabolites) to be the most prevalent GC in this species. An adrenocorticotropic hormone challenge confirmed that fecal corticosterone metabolites are responsive to exogenous stressors and provided validation of the commercial enzyme immunoassay kit used to detect these metabolites. Comparisons of adult female C. sociabilis from natural and captive environments revealed significantly higher baseline concentrations of corticosterone metabolites and significantly greater individual variation in metabolite concentrations among free-living animals. These findings suggest that the natural environment in which these animals occur is more challenging and more variable than the captive housing conditions employed. In addition to providing the first evaluation of GC levels in captive and wild colonial tuco-tucos, our findings indicate that the influence of environmental conditions on stress physiology may have important implications for understanding the social behavior of this species in the laboratory and the field.
动物生存的环境会对其生物学特性产生深远影响，包括对外部应激源的生理反应。为了研究环境条件对群居性土豚鼠（Ctenomys sociabilis）生理应激反应的影响，我们测量了这种社会性地下啮齿动物圈养和自由生活个体的糖皮质激素（GC）水平。对血浆和粪便样本的分析表明，免疫反应性皮质酮（代谢物）是该物种中最普遍的糖皮质激素。促肾上腺皮质激素刺激试验证实，粪便皮质酮代谢物对外源应激源有反应，并验证了用于检测这些代谢物的商业酶免疫分析试剂盒。对来自自然环境和圈养环境的成年雌性群居性土豚鼠的比较显示，自由生活动物的皮质酮代谢物基线浓度显著更高，且代谢物浓度的个体差异更大。这些发现表明，这些动物所处的自然环境比所采用的圈养条件更具挑战性且变化更大。除了首次评估圈养和野生群居性土豚鼠的糖皮质激素水平外，我们的研究结果还表明，环境条件对应激生理学的影响可能对理解该物种在实验室和野外的社会行为具有重要意义。
