title: Comparison of methanol and isopropanol as wash solvents for determination of hair cortisol concentration in grizzly bears and polar bears.
abstract: Methodological differences among laboratories are recognized as significant sources of variation in quantification of hair cortisol concentration (HCC). An important step in processing hair, particularly when collected from wildlife, is the choice of solvent used to remove or "wash" external hair shaft cortisol prior to quantification of HCC. The present study systematically compared methanol and isopropanol as wash solvents for their efficiency at removing external cortisol without extracting internal hair shaft cortisol in samples collected from free-ranging grizzly bears and polar bears. Cortisol concentrations in solvents and hair were determined in each of one to eight washes of hair with each solvent independently. •There were no significant decreases in internal hair shaft cortisol among all eight washes for either solvent, although methanol removed detectable hair surface cortisol after one wash in grizzly bear hair whereas hair surface cortisol was detected in all eight isopropanol washes.•There were no significant differences in polar bear HCC washed one to eight times with either solvent, but grizzly bear HCC was significantly greater in hair washed with isopropanol compared to methanol.•There were significant differences in HCC quantified using different commercial ELISA kits commonly used for HCC determinations.
authors.affiliation: Toxicology Centre, University of Saskatchewan, Saskatoon, SK, S7N 5B3, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kroshko
authors.affiliation: Toxicology Centre, University of Saskatchewan, Saskatoon, SK, S7N 5B3, Canada.
authors.forename: Luciene
authors.initials: L
authors.lastname: Kapronczai
authors.affiliation: RGL Recovery Wildlife Health & Veterinary Services, Saskatoon, SK, S7H 4A6, Canada; Department of Veterinary Pathology, University of Saskatchewan, Saskatoon, SK, S7N 5B4, Canada.
authors.forename: Marc R L
authors.initials: MR
authors.lastname: Cattet
authors.affiliation: Department of Ecosystem and Public Health, University of Calgary, Calgary, AB, T2N 4Z6, Canada.
authors.forename: Bryan J
authors.initials: BJ
authors.lastname: Macbeth
authors.affiliation: Foothills Research Institute, Hinton, AB, T7V 1X6, Canada.
authors.forename: Gordon B
authors.initials: GB
authors.lastname: Stenhouse
authors.affiliation: Wildlife Research and Monitoring Section, Ontario Ministry of Natural Resources and Forestry, Trent University, Peterborough, ON, K9J 7B8, Canada.
authors.forename: Martyn E
authors.initials: ME
authors.lastname: Obbard
authors.affiliation: Department of Veterinary Biomedical Sciences, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK, S7N 5B4, Canada.
authors.forename: David M
authors.initials: DM
authors.lastname: Janz
keywords: Bear; HCC; Hair analysis; Hair cortisol; Hair cortisol concentration; Long-term stress; Wash solvent; Wildlife