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 journalArticlepeer-review

39 Scopus citations


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 languageEnglish (US)
Pages (from-to)R149-R155
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Issue number1 49-1
StatePublished - Jan 2001
Externally publishedYes


  • Follicular cell height
  • Thyroid-stimulating hormone
  • Thyrotrophs
  • Thyroxine

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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