Cold-induced changes in thyroid function in a poikilothermic mammal, the naked mole-rat

Rochelle Buffenstein; Ryan Woodley; Cleopatra Thomadakis; T. Joseph M. Daly; David A. Gray

doi:10.1152/ajpregu.2001.280.1.r149

Cold-induced changes in thyroid function in a poikilothermic mammal, the naked mole-rat

Rochelle Buffenstein, Ryan Woodley, Cleopatra Thomadakis, T. Joseph M. Daly, David A. Gray

Research output: Contribution to journal › Article › peer-review

39 Scopus citations

Abstract

Cold acclimation induces very divergent responses in thyroid function in reptiles and mammals reflective of their different thermoregulatory modes. Naked mole-rats, unlike other small mammals, are unable to effectively employ endothermy and are operatively poikilotherms. We therefore investigated changes in their thyroid status with chronic cold exposure. Under simulated burrow conditions, free thyroxine (T₄; 0.39 ± 0.09 ng/dl) and thyroid stimulating hormone (TSH; 1.12 ± 0.56 μIU/ml) levels fell within the reptilian range, one order of magnitude lower than mammalian levels. However, cold induced typical mammalian responses: free T₄ levels (0.55 ± 0.09 ng/dl) and thyroid follicular cell height were significantly greater. Although TSH levels (1.28 ± 0.83 μIU/ml) were not significantly elevated, thyrotrophs exhibited ultrastructural signs of increased secretory activity. Low thyroid hormone concentrations may contribute substantially to the unusual thermoregulatory mode exhibited by naked mole-rats.

Original language	English (US)
Pages (from-to)	R149-R155
Journal	American Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume	280
Issue number	1 49-1
DOIs	https://doi.org/10.1152/ajpregu.2001.280.1.r149
State	Published - Jan 2001
Externally published	Yes

Keywords

Follicular cell height
Thyroid-stimulating hormone
Thyrotrophs
Thyroxine

ASJC Scopus subject areas

Physiology
Physiology (medical)

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10.1152/ajpregu.2001.280.1.r149

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title = "Cold-induced changes in thyroid function in a poikilothermic mammal, the naked mole-rat",

abstract = "Cold acclimation induces very divergent responses in thyroid function in reptiles and mammals reflective of their different thermoregulatory modes. Naked mole-rats, unlike other small mammals, are unable to effectively employ endothermy and are operatively poikilotherms. We therefore investigated changes in their thyroid status with chronic cold exposure. Under simulated burrow conditions, free thyroxine (T4; 0.39 ± 0.09 ng/dl) and thyroid stimulating hormone (TSH; 1.12 ± 0.56 μIU/ml) levels fell within the reptilian range, one order of magnitude lower than mammalian levels. However, cold induced typical mammalian responses: free T4 levels (0.55 ± 0.09 ng/dl) and thyroid follicular cell height were significantly greater. Although TSH levels (1.28 ± 0.83 μIU/ml) were not significantly elevated, thyrotrophs exhibited ultrastructural signs of increased secretory activity. Low thyroid hormone concentrations may contribute substantially to the unusual thermoregulatory mode exhibited by naked mole-rats.",

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year = "2001",

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AU - Woodley, Ryan

AU - Thomadakis, Cleopatra

AU - Daly, T. Joseph M.

AU - Gray, David A.

PY - 2001/1

Y1 - 2001/1

N2 - Cold acclimation induces very divergent responses in thyroid function in reptiles and mammals reflective of their different thermoregulatory modes. Naked mole-rats, unlike other small mammals, are unable to effectively employ endothermy and are operatively poikilotherms. We therefore investigated changes in their thyroid status with chronic cold exposure. Under simulated burrow conditions, free thyroxine (T4; 0.39 ± 0.09 ng/dl) and thyroid stimulating hormone (TSH; 1.12 ± 0.56 μIU/ml) levels fell within the reptilian range, one order of magnitude lower than mammalian levels. However, cold induced typical mammalian responses: free T4 levels (0.55 ± 0.09 ng/dl) and thyroid follicular cell height were significantly greater. Although TSH levels (1.28 ± 0.83 μIU/ml) were not significantly elevated, thyrotrophs exhibited ultrastructural signs of increased secretory activity. Low thyroid hormone concentrations may contribute substantially to the unusual thermoregulatory mode exhibited by naked mole-rats.

AB - Cold acclimation induces very divergent responses in thyroid function in reptiles and mammals reflective of their different thermoregulatory modes. Naked mole-rats, unlike other small mammals, are unable to effectively employ endothermy and are operatively poikilotherms. We therefore investigated changes in their thyroid status with chronic cold exposure. Under simulated burrow conditions, free thyroxine (T4; 0.39 ± 0.09 ng/dl) and thyroid stimulating hormone (TSH; 1.12 ± 0.56 μIU/ml) levels fell within the reptilian range, one order of magnitude lower than mammalian levels. However, cold induced typical mammalian responses: free T4 levels (0.55 ± 0.09 ng/dl) and thyroid follicular cell height were significantly greater. Although TSH levels (1.28 ± 0.83 μIU/ml) were not significantly elevated, thyrotrophs exhibited ultrastructural signs of increased secretory activity. Low thyroid hormone concentrations may contribute substantially to the unusual thermoregulatory mode exhibited by naked mole-rats.

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Cold-induced changes in thyroid function in a poikilothermic mammal, the naked mole-rat

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Keywords

ASJC Scopus subject areas

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