Journal article
Can offsetting the energetic cost of hibernation restore an active season phenotype in grizzly bears (Ursus arctos horribilis)?
Journal of experimental biology, Vol.224(12)
06/01/2021
PMID: 34137891
Abstract
Hibernation is characterized by depression of many physiological processes. To determine if this state is reversible in a non-food caching species, we fed hibernating grizzly bears (Ursus arctos horribilis) dextrose for 10 days to replace 53% or 100% of the estimated minimum daily energetic cost of hibernation. Feeding caused serum concentrations of glycerol and ketones (beta-hydroxybutyrate) to return to active season levels irrespective of the amount of glucose fed. By contrast, free fatty acids (FFAs) and indices of metabolic rate, such as general activity, heart rate, strength of heart rate circadian rhythm, and insulin sensitivity were restored to approximately 50% of active season levels. Body temperature was unaffected by feeding. To determine the contribution of adipose to the metabolic effects observed after glucose feeding, we cultured bear adipocytes collected at the beginning and end of the feeding and performed metabolic flux analysis. We found a similar to 33% increase in energy metabolism after feeding. Moreover, basal metabolism before feeding was 40% lower in hibernation cells compared with fed cells or active cells cultured at 37 degrees C, thereby confirming the temperature independence of metabolic rate. The partial depression of circulating FFAs with feeding likely explains the incomplete restoration of insulin sensitivity and other metabolic parameters in hibernating bears. Further depression of metabolic function is likely to be an active process. Together, the results provide a highly controlled model to examine the relationship between nutrient availability and metabolism on the hibernation phenotype in bears.
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Details
- Title
- Can offsetting the energetic cost of hibernation restore an active season phenotype in grizzly bears (Ursus arctos horribilis)?
- Creators
- Heiko T. Jansen - Washington State University, Integrative Physiology and Neuroscience, Department ofBrandon Evans Hutzenbiler - Washington State Univ, Coll Vet Med, Dept Integrat Physiol & Neurosci, Pullman, WA 99164 USAHannah R. Hapner - Washington State Univ, Coll Arts & Sci, Sch Biol Sci, Pullman, WA 99164 USAMadeline L. McPhee - Washington State Univ, Coll Vet Med, Dept Integrat Physiol & Neurosci, Pullman, WA 99164 USAAnthony M. Carnahan - Washington State Univ, Coll Arts & Sci, Sch Biol Sci, Pullman, WA 99164 USAJoanna L. Kelley - Washington State University, Biological Sciences, School ofMichael W. Saxton - Washington State Univ, Coll Arts & Sci, Sch Biol Sci, Pullman, WA 99164 USACharles T. Robbins - Washington State University, Environment, School of the (CAHNRS)
- Publication Details
- Journal of experimental biology, Vol.224(12)
- Academic Unit
- Kelley Lab
- Publisher
- Company Biologists Ltd
- Number of pages
- 11
- Grant note
- Nutritional Ecology Fund WSU003675 / International Association for Bear Research and Management Bear Research and Conservation Fund Washington State University endowments: Raili Korkka Brown Bear Fund
- Identifiers
- 99900882930701842
- Language
- English
- Resource Type
- Journal article