Tissue-specific depression of mitochondrial proton leak and substrate oxidation in hibernating arctic ground squirrels

Jamie L. Barger, Martin D. Brand, Brian M. Barnes, Bert Boyer

Research output: Contribution to journalArticle

70 Citations (Scopus)

Abstract

A significant proportion of standard metabolic rate is devoted to driving mitochondrial proton leak, and this futile cycle may be a site of metabolic control during hibernation. To determine if the proton leak pathway is decreased during metabolic depression related to hibernation, mitochondria were isolated from liver and skeletal muscle of nonhibernating (active) and hibernating arctic ground squirrels (Spermophilus parryii). At an assay temperature of 37°C, state 3 and state 4 respiration rates and state 4 membrane potential were significantly depressed in liver mitochondria isolated from hibernators. In contrast, state 3 and state 4 respiration rates and membrane potentials were unchanged during hibernation in skeletal muscle mitochondria. The decrease in oxygen consumption of liver mitochondria was achieved by reduced activity of the set of reactions generating the proton gradient but not by a lowered proton permeability. These results suggest that mitochondrial proton conductance is unchanged during hibernation and that the reduced metabolism in hibernators is a partial consequence of tissue-specific depression of substrate oxidation.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume284
Issue number5 53-5
StatePublished - May 1 2003
Externally publishedYes

Fingerprint

Sciuridae
Hibernation
Protons
Liver Mitochondrion
Respiratory Rate
Membrane Potentials
Skeletal Muscle
Substrate Cycling
Muscle Mitochondrion
Oxygen Consumption
Permeability
Mitochondria
Temperature
Liver

Keywords

  • Hibernation
  • Liver
  • Metabolic depression
  • Skeletal muscle
  • Uncoupling

ASJC Scopus subject areas

  • Physiology

Cite this

Tissue-specific depression of mitochondrial proton leak and substrate oxidation in hibernating arctic ground squirrels. / Barger, Jamie L.; Brand, Martin D.; Barnes, Brian M.; Boyer, Bert.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 284, No. 5 53-5, 01.05.2003.

Research output: Contribution to journalArticle

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