ArticlePloS one2013
Metabolic changes in summer active and anuric hibernating free-ranging brown bears (Ursus arctos).
Article in PloS one, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 33 papers.
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Who cites it
33 citing papers in PubMed, 65 citations in OpenAlex.
- Using Organoids to Unlock the Potential of Human Torpor for Spaceflight.Current stem cell reports · 2026Article
- Active bile acid metabolism could contribute to muscle preservation in hibernating bears via the TGR5 pathway.Pflugers Archiv : European journal of physiology · 2026Article
- Comparative physiology and biomimetics in metabolic and environmental health: what can we learn from extreme animal phenotypes?Diabetologia · 2026Review
- Incorporation of microbially salvaged urea-nitrogen into anabolic amino acids during hibernation in arctic ground squirrels.Communications biology · 2026Article
- Review
- Incorporation of microbially salvaged urea-nitrogen into anabolic amino acids during hibernation in arctic ground squirrels.bioRxiv : the preprint server for biology · 2025Article
- Metabolic depression and non-specific immune response during hibernation of common Asian toad, Duttaphrynus melanostictus.Biology open · 2025Article
- Harnessing Evolution and Biomimetics to Enhance Planetary Health: Kidney Insights.Journal of the American Society of Nephrology : JASN · 2025Review
- Reduced ATP turnover during hibernation in relaxed skeletal muscle.Nature communications · 2025Article
- Formerly bile-farmed bears as a model of accelerated ageing.Scientific reports · 2023Article
- Hypothyroidism in hibernating brown bears.Thyroid research · 2023Article
- The cost of research: Lasting effects of capture, surgery and muscle biopsy on brown bear (Animal welfare (South Mimms, England) · 2023Article
- Article
- Elevated plasma phospholipid n-3 docosapentaenoic acid concentrations during hibernation.PloS one · 2023Article
- Free amino acid and acylcarnitine values in Ursus americanus Pallas 1780 (black bear) from Northeastern Mexico.PloS one · 2023Article
- Changing lanes: seasonal differences in cellular metabolism of adipocytes in grizzly bears (Ursus arctos horribilis).Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2022Article
- Fructose Intake, Hypertension and Cardiometabolic Risk Factors in Children and Adolescents: From Pathophysiology to Clinical Aspects. A Narrative Review.Frontiers in medicine · 2022Review
- Potential natural immunization against atherosclerosis in hibernating bears.Scientific reports · 2021Article
- Body Protein Sparing in Hibernators: A Source for Biomedical Innovation.Frontiers in physiology · 2021Review
- Expression of Paracrine Effectors in Human Adipose-Derived Mesenchymal Stem Cells Treated With Plasma From Brown Bears (Ursus arctos).Clinical and translational science · 2021Article
Corrections and comments
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Authors and funding
15 authors at 9 institutions in 7 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The brown bear (Ursus arctos) hibernates for 5 to 6 months each winter and during this time ingests no food or water and remains anuric and inactive. Despite these extreme conditions, bears do not develop azotemia and preserve their muscle and bone strength. To date most renal studies have been limited to small numbers of bears, often in captive environments. Sixteen free-ranging bears were darted and had blood drawn both during hibernation in winter and summer. Samples were collected for measurement of creatinine and urea, markers of inflammation, the calcium-phosphate axis, and nutritional parameters including amino acids. In winter the bear serum creatinine increased 2.5 fold despite a 2-fold decrease in urea, indicating a remarkable ability to recycle urea nitrogen during hibernation. During hibernation serum calcium remained constant despite a decrease in serum phosphate and a rise in FGF23 levels. Despite prolonged inactivity and reduced renal function, inflammation does not ensue and bears seem to have enhanced antioxidant defense mechanisms during hibernation. Nutrition parameters showed high fat stores, preserved amino acids and mild hyperglycemia during hibernation. While total, essential, non-essential and branched chain amino acids concentrations do not change during hibernation anorexia, changes in individual amino acids ornithine, citrulline and arginine indicate an active, although reduced urea cycle and nitrogen recycling to proteins. Serum uric acid and serum fructose levels were elevated in summer and changes between seasons were positively correlated. Further studies to understand how bears can prevent the development of uremia despite minimal renal function during hibernation could provide new therapeutic avenues for the treatment of human kidney disease.
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