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Busted! First Detection of Steroid Hormones in Pacific Walrus Bones
Poster Title: Busted! First Detection of Steroid Hormones in Pacific Walrus Bones
Submitted on 19 Jan 2015
Author(s): Charapata P, Horstmann L, and Misarti N
Affiliations: University of Alaska Fairbanks School of Fisheries and Ocean Sciences, Museum of the North, and National Science Foundation
This poster was presented at AMSS
Poster Views: 1,364
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Poster Information
Abstract: The Pacific walrus (Odobenus rosmarus divergens) is a candidate for the Endangered Species List, because climate warming could affect habitat use and food web structure. With the current change of the Arctic ecosystem, it is unclear how walruses will respond to these possible stressors. In this novel study, steroid hormones (i.e., progesterone, testosterone, estradiol, estriol, and cortisol) were extracted from archeological (927-3,585 years old), historical (34-81 years old), and modern (year 2014 samples) bones to determine if hormones could be detected in bones of various ages. Lipids were removed and subsequently steroid hormones, from powdered bone using a methanol extraction procedure. Hormone levels were analyzed and validated by liquid chromatography triple quadrupole mass spectrometry (LC-QQQ MS). Progesterone, testosterone, cortisol, and estriol were detected, while estradiol concentrations were below the detection limit (<1 ng/g) in all samples. We were able to detect cortisol in archaeological (n=1 of 7, 3.71 ng/g), historical (n=3 of 52 mean= 4.07 ng/g), and modern (n=1 of 10, 6.56 ng/g) bone samples. Progesterone was detected in archaeological (n=4 of 7, mean= 1.47 ng/g), historical (n=51 of 52, mean=14.76 ng/g), and modern (n=8 of 10, mean=10.08) bone samples. Testosterone was detected in archaeological (n=3 of 7, mean= 0.24 ng/g), historical (n=26 of 52, mean=0.98 ng/g), and modern (n=6 of 10, mean=1.03 ng/g). Estriol was only detected in archaeological (n=7 of 7, mean= 79.04 ng/g) bone samples. These results validate our method of steroid hormone extraction and are the first to address environmental interactions and physiological responses in historic and pre-historic walrus populations. Summary: The Pacific walrus (Odobenus rosmarus divergens) is a candidate species for the Endangered Species List because Arctic sea ice has declined significantly in the past decades. This project focuses on validating a method for extracting steroid hormones from archaeological, historical, and modern bone creating a baseline of hormone levels during different climate regimes. The results validate our method of hormone extraction as all steroid hormones were extracted from bones of all time frames.References: Accorsi P a, Carloni E, Valsecchi P, et al. (2008) Cortisol determination in hair and faeces from domestic cats and dogs. Gen Comp Endocrinol 155:398–402. doi: 10.1016/j.ygcen.2007.07.002
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