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      Can concentrations of steroid hormones in brown bear hair reveal age class?

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          Abstract

          We evaluated if steroid hormone concentration profiles in hair collected from brown bears could be used to discriminate between immature and adult bears. Classification accuracy was excellent for male age classes. We also had good success with accurately classifying adult females, but poor accuracy with classifying immature females.

          Abstract

          Although combining genetic and endocrine data from non-invasively collected hair samples has potential to improve the conservation of threatened mammals, few studies have evaluated this opportunity. In this study, we determined if steroid hormone (testosterone, progesterone, estradiol and cortisol) concentration profiles in 169 hair samples collected from free-ranging brown bears ( Ursus arctos) could be used to accurately discriminate between immature and adult bears within each sex. Because hair samples were acquired opportunistically, we also needed to establish if interactions between hormones and several non-hormone factors (ordinal day, year, contact method, study area) were associated with age class. For each sex, we first compared a suite of candidate models by Akaike Information Criteria model selection, using different adult-age thresholds (3, 4 and 5 years), to determine the most supported adult age. Because hair hormone levels better reflect the endocrine state at an earlier time, possibly during the previous year, then at the time of sampling, we re-analysed the data, excluding the records for bears at the adult-age threshold, to establish if classification accuracy improved. For both sexes, candidate models were most supported based on a 3-year-old adult-age threshold. Classification accuracy did not improve with the 3-year-old bear data excluded. Male age class was predicted with a high degree of accuracy (88.4%) based on the concomitant concentrations of all four hormones. Female age class was predicted with less accuracy (77.1%) based only on testosterone and cortisol. Accuracy was reduced for females, primarily because we had poor success in correctly classifying immature bears (60%) whereas classification success for adult females was similar to that for males (84.5%). Given the small and unbalanced sample used in this study, our findings should be viewed as preliminary, but they should also provide a basis for more comprehensive future studies.

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          Most cited references 78

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          Hair cortisol as a biological marker of chronic stress: current status, future directions and unanswered questions.

          The detrimental effects of stress on human health are being increasingly recognized. There is a critical need for the establishment of a biomarker that accurately measures its intensity and course over time. Such a biomarker would allow monitoring of stress, increase understanding of its pathophysiology and may help identify appropriate and successful management strategies. Whereas saliva and urine cortisol capture real-time levels, hair cortisol analysis presents a complementary means of monitoring stress, capturing systemic cortisol exposure over longer periods of time. This novel approach for cortisol quantification is being increasingly used to identify the effects of stress in a variety of pathological situations, from chronic pain to acute myocardial infarctions. Because of its ability to provide a long-term, month-by-month measure of systemic cortisol exposure, hair cortisol analysis is becoming a useful tool, capable of answering clinical questions that could previously not be answered by other tests. In this paper we review the development, current status, limitations and outstanding questions regarding the use of hair cortisol as a biomarker of chronic stress. Copyright © 2011 Elsevier Ltd. All rights reserved.
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            Resilience and Conservation of Large Carnivores in the Rocky Mountains

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              Steroidogenesis in the skin: implications for local immune functions.

              The skin has developed a hierarchy of systems that encompasses the skin immune and local steroidogenic activities in order to protect the body against the external environment and biological factors and to maintain local homeostasis. Most recently it has been established that skin cells contain the entire biochemical apparatus necessary for production of glucocorticoids, androgens and estrogens either from precursors of systemic origin or, alternatively, through the conversion of cholesterol to pregnenolone and its subsequent transformation to biologically active steroids. Examples of these products are corticosterone, cortisol, testosterone, dihydrotesterone and estradiol. Their local production can be regulated by locally produced corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) or cytokines. Furthermore the production of glucocorticoids is affected by ultraviolet B radiation. The level of production and nature of the final steroid products are dependent on the cell type or cutaneous compartment, e.g., epidermis, dermis, adnexal structures or adipose tissue. Locally produced glucocorticoids, androgens and estrogens affect functions of the epidermis and adnexal structures as well as local immune activity. Malfunction of these steroidogenic activities can lead to inflammatory disorders or autoimmune diseases. The cutaneous steroidogenic system can also have systemic effects, which are emphasized by significant skin contribution to circulating androgens and/or estrogens. Furthermore, local activity of CYP11A1 can produce novel 7Δ-steroids and secosteroids that are biologically active. Therefore, modulation of local steroidogenic activity may serve as a new therapeutic approach for treatment of inflammatory disorders, autoimmune processes or other skin disorders. In conclusion, the skin can be defined as an independent steroidogenic organ, whose activity can affect its functions and the development of local or systemic inflammatory or autoimmune diseases. This article is part of a Special Issue entitled 'CSR 2013'. Copyright © 2013 Elsevier Ltd. All rights reserved.
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                Author and article information

                Journal
                Conserv Physiol
                Conserv Physiol
                conphys
                Conservation Physiology
                Oxford University Press
                2051-1434
                2018
                29 January 2018
                29 January 2018
                : 6
                : 1
                Affiliations
                [1 ] RGL Recovery Wildlife Health & Veterinary Services, 415 Mount Allison Crescent, Saskatoon, Saskatchewan S7H 4A6, Canada,
                [2 ]Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada
                [3 ]fRI Research and Alberta Environment and Parks, 1176 Switzer Drive, Hinton, Alberta T7V 1X6, Canada
                [4 ]Integrated Ecological Research, 924 Innes Street, Nelson, British Columbia V1L 5T2, Canada
                [5 ]Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada
                [6 ]Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, Saskatchewan S7N 5B3, Canada
                [7 ]Faculty of Environmental Sciences and Nature Resource Management, Norwegian University of Life Sciences, PO Box 5003, NO-1432 Ås, Norway and Norwegian Institute for Nature Research, Høgskoleringen 9, 7034 Trondheim, Norway
                [8 ]Department of Natural Sciences and Environmental Health, Telemark University College of Southeast Norway, NO-3800 Bø i Telemark, Norway
                [9 ]Department for Integrative Biology, Institute for Wildlife Biology and Game Management, University for Natural Resources and Life Sciences, Vienna A-1180, Austria
                Author notes
                Corresponding author: RGL Recovery Wildlife Health & Veterinary Services, 415 Mount Allison Crescent, Saskatoon, Saskatchewan S7H 4A6, Canada. Tel: +1 3062803782. Email: rgloperations.mcattet@ 123456gmail.com
                Editor:
                Article
                coy001
                10.1093/conphys/coy001
                5788069
                © The Author(s) 2018. Published by Oxford University Press and the Society for Experimental Biology.

                This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

                Page count
                Pages: 20
                Product
                Funding
                Funded by: the many partners of the fRI Research Grizzly Bear Program
                Funded by: the Saskatoon Forestry Farm Park & Zoo; and from the Scandinavian Brown Bear Research Project
                Funded by: the Swedish Environmental Protection Agency
                Funded by: the Norwegian Environment Agency
                Funded by: the Austrian Science Fund, and the Swedish Association for Hunting and Wildlife Management
                Categories
                Research Article

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