Validation of a radioimmunoassay-based fecal corticosteroid assay for Richardson＇s ground squirrels Urocitellus richardsonii and behavioural correlates of stress

作     者：James F. HARE Calen R RYAN Chris ENRIGHT Laura E. GARDINER Lindsay J SKYNER Charlene N. BERKVENS W. Gary ANDERSON 

作者机构：Department of Biological Sciences University of Manitoba Winnipeg MB Canada R3T 2N2 Assiniboine Park Zoo Winnipeg MB Canada R3R 2N7 Present Address: School of Applied Science Bay of Plenty Polytechnic Tauranga 3112 New Zealand 

出 版 物：《Current Zoology》 (动物学报（英文版）)

年 卷 期：2014年第60卷第5期

页      面：591-601页

核心收录：

学科分类：0710[理学-生物学] 071010[理学-生物化学与分子生物学] 081704[工学-应用化学] 07[理学] 0905[农学-畜牧学] 08[工学] 0817[工学-化学工程与技术] 09[农学] 

基　　金：research was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC) in the form of Discovery Grants to JFH WGA 

主　　题：Stress Corticosteroids Fecal glucocorticoid metabolites Radioimmunoassay Richardson's ground squirrels 

摘      要：We validated a radioimmunoassay-based method quantifying fecal glucocorticoid metabolites （FGMs） from captive male and female Richardson＇s ground squirrels Urocitellus richardsonii. Blood samples were drawn to explore the correlation between plasma cortisol and FGM concentrations. We also injected groups of squirrels with normal saline （CTL; control）, adre- nocorticotropic hormone （ACTH; stimulating adrenal activity）, or dexamethasone （DEX; suppressing adrenal activity）. Potential correlations between stress and behaviour were explored through quantification of fecal pellet production and the intervention necessary to elicit defecation, as well as the behaviour of subjects in the context of handling. Changes in plasma cortisol concen- tration between capture （baseline）, and following handling （stress-induced） were also quantified for free-living squirrels. While glucocorticoid concentrations recovered from feces during our captive-animal study were not well correlated with plasma eortisol concentrations, and uncorrelated with defecation or behaviour, FGM concentrations did reflect the activation of the hypothalamic- pituitary-adrenal （HPA） axis. FGM concentrations increased significantly during initial captivity, but declined to baseline level as individuals acclimated to the novel environment. Injection of subjects with ACTH increased FGMs above baseline, confirming activation of the HPA axis. Plasma cortisol concentrations increased significantly with induced stress, indicating that capture and handling activated the glucocorticoid stress response even among previously handled, free-living subjects. Our findings validate a non-invasive tool that will afford new insight into the physiological processes underlying social, reproductive and antipredator behaviour of Richardson＇s ground squirrels [Current Zoology 60 （5）： 591-601, 2014 ].