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Updated: Jun 2, 2026
06:53
Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures
Published on: November 11, 2016
Metabolic cycles in a circannual hibernator
L Elaine Epperson1, Anis Karimpour-Fard, Lawrence E Hunter
1Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado, USA.
Physiological Genomics
|May 5, 2011
Summary
Hibernation in ground squirrels involves extreme physiological changes. Periodic arousals during hibernation are crucial for restoring metabolic homeostasis after periods of torpor and fasting.
Area of Science:
- Mammalian physiology
- Metabolomics
- Chronobiology
Background:
- Hibernation is an extreme physiological adaptation in mammals, challenging homeostasis through prolonged fasting and heterothermy.
- Ground squirrels exhibit a highly plastic and extreme form of hibernation, requiring sophisticated survival mechanisms.
Purpose of the Study:
- To define metabolite shifts associated with hibernation in ground squirrels using a nontargeted metabolomic approach.
- To identify robust hibernation biomarkers and understand metabolic changes during seasonal and torpor-arousal cycles.
Main Methods:
- LC and GC-MS metabolomic profiling of plasma samples.
- Analysis of samples from seven natural stages of the ground squirrel's annual cycle (3 summer, 4 winter).
- Quantification of 231 named metabolites, with 106 showing significant alterations.
Main Results:
- Identified 106 significantly altered metabolites across hibernation stages.
- Discovered specific biomarkers including free fatty acids, antioxidants, and novel modified amino acids linked to fasting.
- Observed a major pattern of metabolite depletion/accrual during torpor, reversed by interbout arousal.
Conclusions:
- Periodic arousals are essential for restoring metabolic homeostasis during hibernation.
- Metabolite profiles reveal a 'cycle within a cycle' reflecting torpor-arousal dynamics.
- Identified novel biomarkers provide insights into the physiological adaptations during hibernation and fasting.
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