Hypothalamic remodeling of thyroid hormone signaling during hibernation in the arctic ground squirrel

Helen E. Chmura, Cassandra Duncan, Ben Saer, Jeanette T. Moore, Brian M. Barnes, C. Loren Buck, Helen C. Christian, Andrew S.I. Loudon, Cory T. Williams

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Hibernation involves prolonged intervals of profound metabolic suppression periodically interrupted by brief arousals to euthermy, the function of which is unknown. Annual cycles in mammals are timed by a photoperiodically-regulated thyroid-hormone-dependent mechanism in hypothalamic tanycytes, driven by thyrotropin (TSH) in the pars tuberalis (PT), which regulates local TH-converting deiodinases and triggers remodeling of neuroendocrine pathways. We demonstrate that over the course of hibernation in continuous darkness, arctic ground squirrels (Urocitellus parryii) up-regulate the retrograde TSH/Deiodinase/TH pathway, remodel hypothalamic tanycytes, and activate the reproductive axis. Forcing the premature termination of hibernation by warming animals induced hypothalamic deiodinase expression and the accumulation of secretory granules in PT thyrotrophs and pituitary gonadotrophs, but did not further activate the reproductive axis. We suggest that periodic arousals may allow for the transient activation of hypothalamic thyroid hormone signaling, cellular remodeling, and re-programming of brain circuits in preparation for the short Arctic summer.

Original languageEnglish (US)
Article number492
JournalCommunications biology
Issue number1
StatePublished - Dec 2022

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • General Biochemistry, Genetics and Molecular Biology
  • General Agricultural and Biological Sciences


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