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...
Published in: | Thyroid Research |
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Format: | Article in Journal/Newspaper |
Language: | English |
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2023
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Online Access: | https://vbn.aau.dk/da/publications/c1687abe-f0dd-40c4-89d8-37ff97601719 https://doi.org/10.1186/s13044-022-00144-2 https://vbn.aau.dk/ws/files/516624875/Fr_bert_et_al._2023_._Hypothyroidism_in_hibernating_brown_bears.pdf http://www.scopus.com/inward/record.url?scp=85147149936&partnerID=8YFLogxK |
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ftalborgunivpubl:oai:pure.atira.dk:publications/c1687abe-f0dd-40c4-89d8-37ff97601719 2024-06-23T07:57:22+00:00 Hypothyroidism in hibernating brown bears Frøbert, Anne Mette Nielsen, Claus G. Brohus, Malene Kindberg, Jonas Fröbert, Ole Overgaard, Michael T. 2023-02-01 application/pdf https://vbn.aau.dk/da/publications/c1687abe-f0dd-40c4-89d8-37ff97601719 https://doi.org/10.1186/s13044-022-00144-2 https://vbn.aau.dk/ws/files/516624875/Fr_bert_et_al._2023_._Hypothyroidism_in_hibernating_brown_bears.pdf http://www.scopus.com/inward/record.url?scp=85147149936&partnerID=8YFLogxK eng eng https://vbn.aau.dk/da/publications/c1687abe-f0dd-40c4-89d8-37ff97601719 info:eu-repo/semantics/openAccess Frøbert , A M , Nielsen , C G , Brohus , M , Kindberg , J , Fröbert , O & Overgaard , M T 2023 , ' Hypothyroidism in hibernating brown bears ' , Thyroid research , vol. 16 , no. 1 , 3 . https://doi.org/10.1186/s13044-022-00144-2 Hibernation Hypothyroidism Metabolism Thyroid hormone Thyroxine Thyroxine-binding globulin (TBG) Triiodothyronine Ursus arctos article 2023 ftalborgunivpubl https://doi.org/10.1186/s13044-022-00144-2 2024-06-10T15:22:06Z 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 findings shed light on the translational potential of bear hibernation physiology to humans for whom a similar hypometabolic state could be of interest in specific conditions. Article in Journal/Newspaper Ursus arctos Aalborg University's Research Portal Thyroid Research 16 1 |
institution |
Open Polar |
collection |
Aalborg University's Research Portal |
op_collection_id |
ftalborgunivpubl |
language |
English |
topic |
Hibernation Hypothyroidism Metabolism Thyroid hormone Thyroxine Thyroxine-binding globulin (TBG) Triiodothyronine Ursus arctos |
spellingShingle |
Hibernation Hypothyroidism Metabolism Thyroid hormone Thyroxine Thyroxine-binding globulin (TBG) Triiodothyronine Ursus arctos Frøbert, Anne Mette Nielsen, Claus G. Brohus, Malene Kindberg, Jonas Fröbert, Ole Overgaard, Michael T. Hypothyroidism in hibernating brown bears |
topic_facet |
Hibernation Hypothyroidism Metabolism Thyroid hormone Thyroxine Thyroxine-binding globulin (TBG) Triiodothyronine Ursus arctos |
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 findings shed light on the translational potential of bear hibernation physiology to humans for whom a similar hypometabolic state could be of interest in specific conditions. |
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://vbn.aau.dk/da/publications/c1687abe-f0dd-40c4-89d8-37ff97601719 https://doi.org/10.1186/s13044-022-00144-2 https://vbn.aau.dk/ws/files/516624875/Fr_bert_et_al._2023_._Hypothyroidism_in_hibernating_brown_bears.pdf http://www.scopus.com/inward/record.url?scp=85147149936&partnerID=8YFLogxK |
genre |
Ursus arctos |
genre_facet |
Ursus arctos |
op_source |
Frøbert , A M , Nielsen , C G , Brohus , M , Kindberg , J , Fröbert , O & Overgaard , M T 2023 , ' Hypothyroidism in hibernating brown bears ' , Thyroid research , vol. 16 , no. 1 , 3 . https://doi.org/10.1186/s13044-022-00144-2 |
op_relation |
https://vbn.aau.dk/da/publications/c1687abe-f0dd-40c4-89d8-37ff97601719 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1186/s13044-022-00144-2 |
container_title |
Thyroid Research |
container_volume |
16 |
container_issue |
1 |
_version_ |
1802650970756218880 |