Abstract
Species have traditionally been defined as cortisol-dominant or corticosterone-dominant, depending on the glucocorticoid that is reported. To assess the degree of covariance versus independence between cortisol and corticosterone, 245 serum samples belonging to 219 individuals from 18 cortisol-dominant, non-domesticated species (6 mammalian orders) were compared by mass spectrometry. In these samples, which were elevated above baseline, concentration ranges were overlapping for cortisol and corticosterone although cortisol was dominant in every sample except one of 17 bighorn sheep with a corticosterone-biased cortisol-to-corticosterone ratio of 0.17. As expected, cortisol and corticosterone were strongly associated among species (r2=0.8; species with high absolute cortisol tend to have high absolute corticosterone concentrations), with wide variation in the species-average cortisol-to-corticosterone ratio (range 7.5-49) and an even wider ratio range across individuals (0.2-341). However, only 9 out of 13 species with >7 individuals showed a positive association between cortisol and corticosterone among individuals, and repeated measures of the cortisol-to-corticosterone ratio within individuals were weakly associated (CV range 3-136%). We conclude that corticosterone, although at lower concentrations, has the potential to signal independently of cortisol, and should be included in integrated endocrine models of stress responses.
Original language | English |
---|---|
Pages (from-to) | 113-119 |
Number of pages | 7 |
Journal | General and Comparative Endocrinology |
Volume | 177 |
Issue number | 1 |
DOIs | |
State | Published - 15 May 2012 |
Externally published | Yes |
Bibliographical note
Funding Information:We are grateful to Lori Rogers from the Calgary Zoo, Pat Curry from the University of Calgary, and the Scandinavian Brown Bear Project, who were instrumental in collecting the mammalian serum samples. Ella Ng and Lea Bond helped with the glucocorticoid analysis. Kim L. Schmidt and Dr. Andrea De Souza provided valuable comments on the manuscript, and Dr. Eli Geffen provided statistical advice. This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada , the Canadian Foundation for Innovation , Alberta Education and Technology , and the Faculty of Veterinary Medicine at the University of Calgary (K.E.W.E.), as well as a postdoctoral fellowship from the University of Calgary Faculty of Veterinary Medicine (L.K./K.E.W.E.). Preliminary results were presented as a poster at the 2011 Society for Behavioral Neuroendocrinology Conference in Querétaro, Mexico with the support of a trainee travel award to L.K.
Funding
We are grateful to Lori Rogers from the Calgary Zoo, Pat Curry from the University of Calgary, and the Scandinavian Brown Bear Project, who were instrumental in collecting the mammalian serum samples. Ella Ng and Lea Bond helped with the glucocorticoid analysis. Kim L. Schmidt and Dr. Andrea De Souza provided valuable comments on the manuscript, and Dr. Eli Geffen provided statistical advice. This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada , the Canadian Foundation for Innovation , Alberta Education and Technology , and the Faculty of Veterinary Medicine at the University of Calgary (K.E.W.E.), as well as a postdoctoral fellowship from the University of Calgary Faculty of Veterinary Medicine (L.K./K.E.W.E.). Preliminary results were presented as a poster at the 2011 Society for Behavioral Neuroendocrinology Conference in Querétaro, Mexico with the support of a trainee travel award to L.K.
Funders | Funder number |
---|---|
Alberta Education and Technology | |
Canadian Foundation for Innovation | |
Faculty of Veterinary Medicine, University of Calgary | |
Natural Sciences and Engineering Research Council of Canada |
Keywords
- Glucocorticoids
- LC-MS/MS
- Mammals
- SPE
- Serum
- Stress