Hypothyroidism in hibernating brown bears
Abstract 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...
Published in: | Thyroid Research |
---|---|
Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
BMC
2023
|
Subjects: | |
Online Access: | https://doi.org/10.1186/s13044-022-00144-2 https://doaj.org/article/83a5468c81124b5db493f59e60d4abcc |
id |
ftdoajarticles:oai:doaj.org/article:83a5468c81124b5db493f59e60d4abcc |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:83a5468c81124b5db493f59e60d4abcc 2023-05-15T18:42:14+02:00 Hypothyroidism in hibernating brown bears Anne Mette Frøbert Claus G. Nielsen Malene Brohus Jonas Kindberg Ole Fröbert Michael T. Overgaard 2023-02-01T00:00:00Z https://doi.org/10.1186/s13044-022-00144-2 https://doaj.org/article/83a5468c81124b5db493f59e60d4abcc EN eng BMC https://doi.org/10.1186/s13044-022-00144-2 https://doaj.org/toc/1756-6614 doi:10.1186/s13044-022-00144-2 1756-6614 https://doaj.org/article/83a5468c81124b5db493f59e60d4abcc Thyroid Research, Vol 16, Iss 1, Pp 1-8 (2023) Thyroid hormone Thyroxine Triiodothyronine Thyroxine-binding globulin (TBG) Ursus arctos Hibernation Diseases of the endocrine glands. Clinical endocrinology RC648-665 article 2023 ftdoajarticles https://doi.org/10.1186/s13044-022-00144-2 2023-02-12T01:32:39Z Abstract 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 Directory of Open Access Journals: DOAJ Articles Thyroid Research 16 1 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Thyroid hormone Thyroxine Triiodothyronine Thyroxine-binding globulin (TBG) Ursus arctos Hibernation Diseases of the endocrine glands. Clinical endocrinology RC648-665 |
spellingShingle |
Thyroid hormone Thyroxine Triiodothyronine Thyroxine-binding globulin (TBG) Ursus arctos Hibernation Diseases of the endocrine glands. Clinical endocrinology RC648-665 Anne Mette Frøbert Claus G. Nielsen Malene Brohus Jonas Kindberg Ole Fröbert Michael T. Overgaard Hypothyroidism in hibernating brown bears |
topic_facet |
Thyroid hormone Thyroxine Triiodothyronine Thyroxine-binding globulin (TBG) Ursus arctos Hibernation Diseases of the endocrine glands. Clinical endocrinology RC648-665 |
description |
Abstract 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 |
Anne Mette Frøbert Claus G. Nielsen Malene Brohus Jonas Kindberg Ole Fröbert Michael T. Overgaard |
author_facet |
Anne Mette Frøbert Claus G. Nielsen Malene Brohus Jonas Kindberg Ole Fröbert Michael T. Overgaard |
author_sort |
Anne Mette Frøbert |
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 |
publisher |
BMC |
publishDate |
2023 |
url |
https://doi.org/10.1186/s13044-022-00144-2 https://doaj.org/article/83a5468c81124b5db493f59e60d4abcc |
genre |
Ursus arctos |
genre_facet |
Ursus arctos |
op_source |
Thyroid Research, Vol 16, Iss 1, Pp 1-8 (2023) |
op_relation |
https://doi.org/10.1186/s13044-022-00144-2 https://doaj.org/toc/1756-6614 doi:10.1186/s13044-022-00144-2 1756-6614 https://doaj.org/article/83a5468c81124b5db493f59e60d4abcc |
op_doi |
https://doi.org/10.1186/s13044-022-00144-2 |
container_title |
Thyroid Research |
container_volume |
16 |
container_issue |
1 |
_version_ |
1766231855313453056 |