[MARMAM] New paper: Recovering cortisol from harbour porpoise skin
Thea Østergaard Bechshøft
thbe at bios.au.dk
Wed Apr 29 09:30:25 PDT 2015
I am very happy to finally be able to share our new paper with you (published open access):
Bechshoft T, Wright AJ, Weisser JJ, Teilmann J, Dietz R, Hansen M, Björklund E, Styrishave B (2015) Developing a new research tool for use
in free-ranging cetaceans: recovering cortisol from harbour porpoise skin. Conserv Physiol 3: doi:10.1093/conphys/cov016.
We developed a chemical analytical procedure for sampling, extracting and determining epidermal skin cortisol concentrations (SCCs) in the harbour porpoise (Phocoena phocoena) using gas chromatography-tandem mass spectrometry. In brief, this involved a pressurized liquid extraction with a two-step solid-phase clean-up. A derivatization step was conducted prior to detection. To evaluate the new assay, cortisol was analysed in three different sample types obtained from four harbour porpoises: skin plates, dorsal fin skin plugs (with and without lidocaine) and epidermal scrapes. Skin cortisol concentrations could be measured using the new assay in the majority of the tested skin samples down to a minimal sample size of 49 mg dry weight (dw). Water content ranged from 10 to 46% in the plug samples, which had SCCs from 2.1 to 77.7 ng/g dw. Epidermal scrape samples had the highest water content (83-87%) and lower SCCs (0.6-15 ng/g dw), while the skin plates had intermediate water contents (60-66%) and SCCs of 2.6-13.0 ng/g dw. SCC was slightly higher in plugs with lidocaine than without (average values of 41 and 33 ng/g dw, respectively). Substantial within-individual variations in cortisol concentrations are also common in other matrices such as blood and hair. Some important factors behind this variation could be e.g. the animal's sex, age, body condition, reproductive stage, and the body region sampled, as well as season, moulting cycles and water temperature. Clearly, more research into SCCs is required. The findings described here represent the first critical steps towards using epidermal skin cell samples to assess chronic stress levels in cetaceans and the development of a widely applicable health-assessment tool in these species.
For a pdf copy, see: http://conphys.oxfordjournals.org/content/3/1/cov016.abstract
Please don't hesitate to contact me if you have any questions.
Thea Bechshøft, Biologist, MSc, PhD
Department of Bioscience
Frederiksborgvej 399, PO Box 358
4000 Roskilde, Denmark
E-mail: thbe at dmu.dk<mailto:thbe at dmu.dk>
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