Hypothyroidism in hibernating brown bears
Brown bears hibernate throughout half of the year as a survival strategy to reduce energy consumption during prolonged periods with scarcity of food and water. Thyroid hormones are the major endocrine regulators of basal metabolic rate in humans. Therefore, we aimed to determine regulations in serum...
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Online Access: | https://hdl.handle.net/11250/3092423 https://doi.org/10.1186/s13044-022-00144-2 |
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ftninstnf:oai:brage.nina.no:11250/3092423 2023-10-29T02:40:45+01:00 Hypothyroidism in hibernating brown bears Frøbert, Anne Mette Nielsen, Claus G. Brohus, Malene Kindberg, Jonas Fröbert, Ole Overgaard, Michael T. Scandinavia, Skandinavia 2023 application/pdf https://hdl.handle.net/11250/3092423 https://doi.org/10.1186/s13044-022-00144-2 eng eng Andre: Lundbeck Foundation R286-2018–367 Andre: Lundbeck Foundation R126- 2012–12408 urn:issn:1756-6614 https://hdl.handle.net/11250/3092423 https://doi.org/10.1186/s13044-022-00144-2 cristin:2123457 Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no © 2023 The Authors 16 Thyroid Research 1 3 Thyroid hormone Thyroxine Triiodothyronine Thyroxine-binding globulin (TBG) Ursus arctos Hibernation Hypothyroidism Metabolism VDP::Zoologiske og botaniske fag: 480 VDP::Zoology and botany: 480 Peer reviewed Journal article 2023 ftninstnf https://doi.org/10.1186/s13044-022-00144-2 2023-10-04T22:48:59Z Brown bears hibernate throughout half of the year as a survival strategy to reduce energy consumption during prolonged periods with scarcity of food and water. Thyroid hormones are the major endocrine regulators of basal metabolic rate in humans. Therefore, we aimed to determine regulations in serum thyroid hormone levels in hibernation compared to the active state to investigate if these are involved in the adaptions for hibernation. We used electrochemiluminescence immunoassay to quantify total triiodothyronine (T3) and thyroxine (T4) levels in hibernation and active state in paired serum samples from six subadult Scandinavian brown bears. Additionally, we determined regulations in the liver mRNA levels of three major thyroid hormone-binding proteins; thyroxine-binding globulin (TBG), transthyretin (TTR), and albumin, by analysis of previously published grizzly bear RNA sequencing data. We found that bears were hypothyroid when hibernating with T4 levels reduced to less than 44% (P=0.008) and T3 levels reduced to less than 36% (P=0.016) of those measured in the active state. In hibernation, mRNA levels of TBG and albumin increased to 449% (P=0.031) and 121% (P=0.031), respectively, of those measured in the active state. TTR mRNA levels did not change. Hibernating bears are hypothyroid and share physiologic features with hypothyroid humans, including decreased basal metabolic rate, bradycardia, hypothermia, and fatigue. We speculate that decreased thyroid hormone signaling is a key mediator of hibernation physiology in bears. Our fndings shed light on the translational potential of bear hibernation physiology to humans for whom a similar hypometabolic state could be of interest in specifc conditions. Thyroid hormone, Thyroxine, Triiodothyronine, Thyroxine-binding globulin (TBG), Ursus arctos, Hibernation, Hypothyroidism, Metabolism publishedVersion Article in Journal/Newspaper Ursus arctos Norwegian Institute for Nature Research: Brage NINA Thyroid Research 16 1 |
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Open Polar |
collection |
Norwegian Institute for Nature Research: Brage NINA |
op_collection_id |
ftninstnf |
language |
English |
topic |
Thyroid hormone Thyroxine Triiodothyronine Thyroxine-binding globulin (TBG) Ursus arctos Hibernation Hypothyroidism Metabolism VDP::Zoologiske og botaniske fag: 480 VDP::Zoology and botany: 480 |
spellingShingle |
Thyroid hormone Thyroxine Triiodothyronine Thyroxine-binding globulin (TBG) Ursus arctos Hibernation Hypothyroidism Metabolism VDP::Zoologiske og botaniske fag: 480 VDP::Zoology and botany: 480 Frøbert, Anne Mette Nielsen, Claus G. Brohus, Malene Kindberg, Jonas Fröbert, Ole Overgaard, Michael T. Hypothyroidism in hibernating brown bears |
topic_facet |
Thyroid hormone Thyroxine Triiodothyronine Thyroxine-binding globulin (TBG) Ursus arctos Hibernation Hypothyroidism Metabolism VDP::Zoologiske og botaniske fag: 480 VDP::Zoology and botany: 480 |
description |
Brown bears hibernate throughout half of the year as a survival strategy to reduce energy consumption during prolonged periods with scarcity of food and water. Thyroid hormones are the major endocrine regulators of basal metabolic rate in humans. Therefore, we aimed to determine regulations in serum thyroid hormone levels in hibernation compared to the active state to investigate if these are involved in the adaptions for hibernation. We used electrochemiluminescence immunoassay to quantify total triiodothyronine (T3) and thyroxine (T4) levels in hibernation and active state in paired serum samples from six subadult Scandinavian brown bears. Additionally, we determined regulations in the liver mRNA levels of three major thyroid hormone-binding proteins; thyroxine-binding globulin (TBG), transthyretin (TTR), and albumin, by analysis of previously published grizzly bear RNA sequencing data. We found that bears were hypothyroid when hibernating with T4 levels reduced to less than 44% (P=0.008) and T3 levels reduced to less than 36% (P=0.016) of those measured in the active state. In hibernation, mRNA levels of TBG and albumin increased to 449% (P=0.031) and 121% (P=0.031), respectively, of those measured in the active state. TTR mRNA levels did not change. Hibernating bears are hypothyroid and share physiologic features with hypothyroid humans, including decreased basal metabolic rate, bradycardia, hypothermia, and fatigue. We speculate that decreased thyroid hormone signaling is a key mediator of hibernation physiology in bears. Our fndings shed light on the translational potential of bear hibernation physiology to humans for whom a similar hypometabolic state could be of interest in specifc conditions. Thyroid hormone, Thyroxine, Triiodothyronine, Thyroxine-binding globulin (TBG), Ursus arctos, Hibernation, Hypothyroidism, Metabolism publishedVersion |
format |
Article in Journal/Newspaper |
author |
Frøbert, Anne Mette Nielsen, Claus G. Brohus, Malene Kindberg, Jonas Fröbert, Ole Overgaard, Michael T. |
author_facet |
Frøbert, Anne Mette Nielsen, Claus G. Brohus, Malene Kindberg, Jonas Fröbert, Ole Overgaard, Michael T. |
author_sort |
Frøbert, Anne Mette |
title |
Hypothyroidism in hibernating brown bears |
title_short |
Hypothyroidism in hibernating brown bears |
title_full |
Hypothyroidism in hibernating brown bears |
title_fullStr |
Hypothyroidism in hibernating brown bears |
title_full_unstemmed |
Hypothyroidism in hibernating brown bears |
title_sort |
hypothyroidism in hibernating brown bears |
publishDate |
2023 |
url |
https://hdl.handle.net/11250/3092423 https://doi.org/10.1186/s13044-022-00144-2 |
op_coverage |
Scandinavia, Skandinavia |
genre |
Ursus arctos |
genre_facet |
Ursus arctos |
op_source |
16 Thyroid Research 1 3 |
op_relation |
Andre: Lundbeck Foundation R286-2018–367 Andre: Lundbeck Foundation R126- 2012–12408 urn:issn:1756-6614 https://hdl.handle.net/11250/3092423 https://doi.org/10.1186/s13044-022-00144-2 cristin:2123457 |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no © 2023 The Authors |
op_doi |
https://doi.org/10.1186/s13044-022-00144-2 |
container_title |
Thyroid Research |
container_volume |
16 |
container_issue |
1 |
_version_ |
1781069356123291648 |