The effects of body region, season and external arsenic application on hair cortisol concentration.

Madison Acker,Gabriela Mastromonaco,Albrecht I Schulte-Hostedde

doi:10.1093/conphys/coy037

Madison Acker, Gabriela Mastromonaco + Show 1 more

Open Access

https://doi.org/10.1093/conphys/coy037

Copy DOI

Journal: Conservation physiology	Publication Date: Jan 1, 2018
Citations: 31	License type: CC BY 4.0

Affiliation: Laurentian University, Toronto Zoo

Abstract

Hair cortisol analysis has been used to quantify hormone levels in circulation in several mammal species. Hair remains stable for decades or centuries, allowing researchers to use archived hair samples to investigate hormone levels that span long time periods. However, several studies have found that intra-individual variability, driven by the body region from which a sample is derived, confounds measurements of systemic glucocorticoid hormone concentrations. In addition, the external application of chemical agents to hair can remove or concentrate molecules of interest. These may preclude the use of samples that have been collected opportunistically and/or those that have been housed in museum collections. Using a captive population of Vancouver Island marmots (Marmota vancouverensis), we found a strong effect of body region on the concentration of cortisol within hair, as well as an effect of season. Using a collection of American mink (Neovison vison) pelts, we found that application of the preservative arsenic in the form of a soap does not cause a significant decrease in cortisol. The marmot results suggest that intra-individual variability is not stable through time. The reason for these seasonal effects is not clear and further study is necessary. Researchers using samples from an unknown body region should exercise caution in interpreting their results. The mink results suggest that samples held in museum collections can be used to quantify cortisol, even when arsenic preservation is suspected.

Highlights

Hair can be used as a substrate with which to quantify molecules found in the circulatory system of mammals, including hormones (Yang et al, 1998; Koren et al, 2002), metals (Sobanska, 2005; Bocharova et al, 2013) and xenobiotics (Baumgartner et al, 1989; D’Havé et al, 2005)
Several validation studies have shown that a single adrenocorticotrophic hormone (ACTH) injection does not lead to increased hair cortisol in captive ungulates (Rangifer tarandus granti and R. tarandus tarandus, (Ashley et al, 2011)) but that repeated ACTH challenge does lead to increased hair cortisol levels in captive
The hair cortisol concentration in Vancouver Island marmot (M. vancouverensis) hair varied with body region

Summary

Introduction

Hair can be used as a substrate with which to quantify molecules found in the circulatory system of mammals, including hormones (Yang et al, 1998; Koren et al, 2002), metals (Sobanska, 2005; Bocharova et al, 2013) and xenobiotics (Baumgartner et al, 1989; D’Havé et al, 2005). Several validation studies have shown that a single adrenocorticotrophic hormone (ACTH) injection does not lead to increased hair cortisol in captive ungulates (Rangifer tarandus granti and R. tarandus tarandus, (Ashley et al, 2011)) but that repeated ACTH challenge does lead to increased hair cortisol levels in captive. Yu et al (2015) found increased levels of corticosterone in the hair of mice subjected to a social defeat paradigm, an experimental design intended to induce chronic stress. These findings suggest that GC levels in hair accurately reflect long-term changes in HPA activity and that these changes are related to systemic GC levels

Methods

Results

Conclusion