Environmental heterogeneity affects seasonal variation in thyroid hormone physiology of free-living arctic ground squirrels ( Urocitellus parryii)
Thyroid hormones (TH) are key regulators of metabolism that could play an important role in altering physiology and energy allocation across life-history stages. Here, we examine seasonal TH dynamics from 345 plasma samples collected from 134 free-living arctic ground squirrels (Urocitellus parryii...
Published in: | Canadian Journal of Zoology |
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Online Access: | http://dx.doi.org/10.1139/cjz-2018-0302 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjz-2018-0302 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjz-2018-0302 |
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crcansciencepubl:10.1139/cjz-2018-0302 2024-06-23T07:50:09+00:00 Environmental heterogeneity affects seasonal variation in thyroid hormone physiology of free-living arctic ground squirrels ( Urocitellus parryii) Williams, Cory T. Chmura, Helen E. Zhang, Victor Dillon, Danielle Wilsterman, Kathryn Barnes, Brian M. Buck, C. Loren 2019 http://dx.doi.org/10.1139/cjz-2018-0302 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjz-2018-0302 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjz-2018-0302 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 97, issue 9, page 783-790 ISSN 0008-4301 1480-3283 journal-article 2019 crcansciencepubl https://doi.org/10.1139/cjz-2018-0302 2024-06-06T04:11:18Z Thyroid hormones (TH) are key regulators of metabolism that could play an important role in altering physiology and energy allocation across life-history stages. Here, we examine seasonal TH dynamics from 345 plasma samples collected from 134 free-living arctic ground squirrels (Urocitellus parryii (Richardson, 1825)) across three consecutive years (2014–2016). We also examine whether unbound levels of triiodothyronine (free T 3 ) in plasma are correlated with total T 3 levels and total thyroxine (T 4 ) levels, and whether fecal T 3 metabolite levels correlate with plasma TH levels. We found significant differences in plasma TH levels across stages of the annual cycle, but these differences were highly inconsistent across years. However, within a given time period, pregnant females had lower free T 3 levels compared with lactating females. We also found that although free T 3 was correlated with both total T 3 and total T 4 in plasma, fecal T 3 was not positively correlated with plasma TH levels. Given the lack of consistent differences across life-history stages, we suggest environmental heterogeneity may be the primary driver of TH dynamics, masking any potential endogenous seasonal rhythms in TH secretion. We urge caution in the use of fecal T 3 metabolites as a proxy for circulating levels and encourage further research to understand the observed discrepancy. Article in Journal/Newspaper Arctic Urocitellus parryii Canadian Science Publishing Arctic Canadian Journal of Zoology 97 9 783 790 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
Thyroid hormones (TH) are key regulators of metabolism that could play an important role in altering physiology and energy allocation across life-history stages. Here, we examine seasonal TH dynamics from 345 plasma samples collected from 134 free-living arctic ground squirrels (Urocitellus parryii (Richardson, 1825)) across three consecutive years (2014–2016). We also examine whether unbound levels of triiodothyronine (free T 3 ) in plasma are correlated with total T 3 levels and total thyroxine (T 4 ) levels, and whether fecal T 3 metabolite levels correlate with plasma TH levels. We found significant differences in plasma TH levels across stages of the annual cycle, but these differences were highly inconsistent across years. However, within a given time period, pregnant females had lower free T 3 levels compared with lactating females. We also found that although free T 3 was correlated with both total T 3 and total T 4 in plasma, fecal T 3 was not positively correlated with plasma TH levels. Given the lack of consistent differences across life-history stages, we suggest environmental heterogeneity may be the primary driver of TH dynamics, masking any potential endogenous seasonal rhythms in TH secretion. We urge caution in the use of fecal T 3 metabolites as a proxy for circulating levels and encourage further research to understand the observed discrepancy. |
format |
Article in Journal/Newspaper |
author |
Williams, Cory T. Chmura, Helen E. Zhang, Victor Dillon, Danielle Wilsterman, Kathryn Barnes, Brian M. Buck, C. Loren |
spellingShingle |
Williams, Cory T. Chmura, Helen E. Zhang, Victor Dillon, Danielle Wilsterman, Kathryn Barnes, Brian M. Buck, C. Loren Environmental heterogeneity affects seasonal variation in thyroid hormone physiology of free-living arctic ground squirrels ( Urocitellus parryii) |
author_facet |
Williams, Cory T. Chmura, Helen E. Zhang, Victor Dillon, Danielle Wilsterman, Kathryn Barnes, Brian M. Buck, C. Loren |
author_sort |
Williams, Cory T. |
title |
Environmental heterogeneity affects seasonal variation in thyroid hormone physiology of free-living arctic ground squirrels ( Urocitellus parryii) |
title_short |
Environmental heterogeneity affects seasonal variation in thyroid hormone physiology of free-living arctic ground squirrels ( Urocitellus parryii) |
title_full |
Environmental heterogeneity affects seasonal variation in thyroid hormone physiology of free-living arctic ground squirrels ( Urocitellus parryii) |
title_fullStr |
Environmental heterogeneity affects seasonal variation in thyroid hormone physiology of free-living arctic ground squirrels ( Urocitellus parryii) |
title_full_unstemmed |
Environmental heterogeneity affects seasonal variation in thyroid hormone physiology of free-living arctic ground squirrels ( Urocitellus parryii) |
title_sort |
environmental heterogeneity affects seasonal variation in thyroid hormone physiology of free-living arctic ground squirrels ( urocitellus parryii) |
publisher |
Canadian Science Publishing |
publishDate |
2019 |
url |
http://dx.doi.org/10.1139/cjz-2018-0302 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjz-2018-0302 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjz-2018-0302 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Urocitellus parryii |
genre_facet |
Arctic Urocitellus parryii |
op_source |
Canadian Journal of Zoology volume 97, issue 9, page 783-790 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/cjz-2018-0302 |
container_title |
Canadian Journal of Zoology |
container_volume |
97 |
container_issue |
9 |
container_start_page |
783 |
op_container_end_page |
790 |
_version_ |
1802641026754543616 |