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Titolo:
The effect of metabolic depression on proton leak rate in mitochondria from hibernating frogs
Autore:
St-Pierre, J; Brand, MD; Boutilier, RG;
Indirizzi:
Univ Cambridge, Dept Zool, Cambridge CB2 3EJ, England Univ Cambridge Cambridge England CB2 3EJ ool, Cambridge CB2 3EJ, England Univ Cambridge, Dept Biochem, Cambridge CB2 1QW, England Univ Cambridge Cambridge England CB2 1QW hem, Cambridge CB2 1QW, England
Titolo Testata:
JOURNAL OF EXPERIMENTAL BIOLOGY
fascicolo: 9, volume: 203, anno: 2000,
pagine: 1469 - 1476
SICI:
0022-0949(200005)203:9<1469:TEOMDO>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
INNER MEMBRANE PHOSPHOLIPIDS; FATTY-ACID COMPOSITION; LIVER-MITOCHONDRIA; OXIDATIVE-PHOSPHORYLATION; GROUND-SQUIRRELS; CITELLUS-UNDULATUS; ENERGY-METABOLISM; RESPIRATORY-CHAIN; ESTIVATING SNAILS; OBESE RATS;
Keywords:
proton leak; mitochondria; metabolic depression; skeletal muscle; hypoxia; normoxia; hibernation; electron transport chain; frog; Rana temporaria; state 4; proton conductance;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
50
Recensione:
Indirizzi per estratti:
Indirizzo: St-Pierre, J Univ Cambridge, Dept Zool, Downing St, Cambridge CB2 3EJ, England Univ Cambridge Downing St Cambridge England CB2 3EJ England
Citazione:
J. St-Pierre et al., "The effect of metabolic depression on proton leak rate in mitochondria from hibernating frogs", J EXP BIOL, 203(9), 2000, pp. 1469-1476

Abstract

Futile cycling of protons across the mitochondrial inner membrane accountsfor 20% or more of the total standard metabolic rate of a rat. Approximately 15% of this total is due to proton leakage inside the skeletal muscle alone. This study examined whether the rate of proton leak is downregulated as a part of a coordinated response to energy conservation during metabolic depression in cold-submerged frogs. We compared the proton leak rate of skeletal muscle mitochondria isolated from frogs at different stages of hibernation (control, 1 month and 4 months of submergence ill normoxia and hypoxia). The kinetics of mitochondrial proton leak rate was unaltered throughoutnormoxic and hypoxic submergence. The state 4 respiration rates did not differ between control animals and frogs hibernating in normoxia. In contrast, the state 4 respiration rates obtained from frogs submerged in hypoxic water for 4 months were half those of control animals, This 50% reduction in respiration rate in hypoxic hibernation was due to a reduction in electron transport chain activity and consequent decrease in mitochondrial membrane potential. We conclude that proton leak rate is reduced during metabolic depression as a secondary result of a decrease in electron transport chain activity, but that the proton conductance is unchanged. In addition, we show that the rate of proton leakage and the activity of the electron transport chain are lower in frogs than in rats, strengthening the observation that mitochondria from ectotherms have a lower proton conductance than mitochondria from endotherms.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 18/01/20 alle ore 01:42:25