Body mass dependence of H+ leak in mitochondria and its relevance to metabolic rate

Porter, Richard K.; Brand, Martin D.

doi:10.1038/362628a0

Cited by 240 publications

(153 citation statements)

References 18 publications

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“…In a series of papers over the past decade, they have provided convincing theoretical [179] and experimental [7,9] evidence that the mitochondrial leakage current is a major contributor to whole-body basal metabolic rate. They have emphasized the difficulty of estimating the contribution of this component from in vitro studies by using isolated mitochondria [180,181] in which, for example, the use of oligomycin to abolish oxidative phosphorylation (and therefore to reveal proton leak-dependent oxidation) necessarily increases ⌬⌿ (the mitochondrial voltage gradient).…”

Section: Contributors To the Energymentioning

confidence: 99%

“…The one clear effect of substrates [218,223] is that they do significantly alter the inner mitochondrial membrane potential. Thus it is common to find that switching from glucose to pyruvate produces large changes in the mitochondrial membrane potential ranging from Ϫ110 to Ϫ120 mV in glucose, at low energy demand, to values of about Ϫ150 mV in pyruvate where the higher membrane potential will be associated with a greater proton leak [1,7].…”

Section: Modifiers Of Basal Metabolismmentioning

confidence: 99%

“…The ratio of mitochondrial to cell volume is higher in the smaller species [6], and the mitochondria in the smaller mammals have a higher proton leak [7], thus establishing a cellular futile cycle. It is also well known that the protein turnover rate increases in the smaller species [8].…”

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confidence: 99%

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Cardiac Basal Metabolism.

Gibbs

Loiselle²

2001

JJP

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The cardiac basal metabolism is the rate of energy expenditure of the quiescent myocardium. It is also called the resting metabolism or the arrested heart metabolism. It has been measured in numerous ways, and in vivo there is good evidence that it accounts for about 1/5 to 1/3 of the total energy flux. The difficulty arises, however, when the heart is stopped because the magnitude of the basal metabolism depends, as blood viscosity, on how and under what physiological condition it is measured. It is possible for the in vivo basal value to fall to less than 1/5 of its original value without cellular damage or to increase to values 5 times greater than its probable in vivo magnitude (i.e., to rise to values in excess of the energy flux of the normally beating heart) by altering the composition of the perfusion medium. We have written on this subject several times [1][2][3], but believe that developments in knowledge now make it possible for us to speculate in a more informed manner. Since several million openheart operations are performed on arrested hearts worldwide each year, it would seem imperative that we understand the cellular mechanisms that can change the magnitude of basal metabolism.A. V. Hill [4] has pointed out that in examining physiological activities, it is necessary to assume a baseline from which some quantity or rate can be measured. If the energy flux produced by the beating heart were very large compared with the energy flux of the arrested heart, baseline ambiguity would be relatively unimportant. But this is not so in regard to the heart; its basal metabolism is high. Within a species, the basal metabolism of cardiac tissue is several-fold higher than the resting metabolism of skeletal muscle and is an order of magnitude greater than the resting metabolism of amphibian skeletal muscle.Species differences are clearly evident in the magnitude of cardiac basal metabolism, and we believe that the major reason for these differences relates to the leakiness of cell membranes, such as those of the sarcolemma and sarcoplasmic reticulum and those of Japanese Journal of Physiology, 51, 399-426, 2001 Key words: whole hearts, isolated preparations, biochemical contributors, modifiers, species difference, temperature, substrate, hypoxia. Abstract:We endeavor to show that the metabolism of the nonbeating heart can vary over an extreme range: from values approximating those measured in the beating heart to values of only a small fraction of normal-perhaps mimicking the situation of nonflow arrest during cardiac bypass surgery. We discuss some of the technical issues that make it difficult to establish the magnitude of basal metabolism in vivo. We consider some of the likely contributors to its magnitude and point out that the biochemical reasons for a sizable fraction of the heart's basal ATP usage remain unresolved. We consider many of the physiological factors that can alter the basal metabolic rate, stressing the importance of substrate supply. We point out that the protective effect of hypothermia ...

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Section: Contributors To the Energymentioning

confidence: 99%

Section: Modifiers Of Basal Metabolismmentioning

confidence: 99%

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Cardiac Basal Metabolism.

Gibbs

Loiselle²

2001

JJP

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“…Taken together, these studies put forward the hypothesis that basal proton leak significantly contributes to BMR. The correlation between massspecific BMR and mitochondrial proton leak (per mg of protein), both of them scaling negatively with body mass, has been established over the past 20 years in eutherian mammals [18].…”

Section: Introductionmentioning

confidence: 99%

Phylogenetic differences of mammalian basal metabolic rate are not explained by mitochondrial basal proton leak

et al. 2011

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Metabolic rates of mammals presumably increased during the evolution of endothermy, but molecular and cellular mechanisms underlying basal metabolic rate (BMR) are still not understood. It has been established that mitochondrial basal proton leak contributes significantly to BMR. Comparative studies among a diversity of eutherian mammals showed that BMR correlates with body mass and proton leak. Here, we studied BMR and mitochondrial basal proton leak in liver of various marsupial species. Surprisingly, we found that the mitochondrial proton leak was greater in marsupials than in eutherians, although marsupials have lower BMRs. To verify our finding, we kept similar-sized individuals of a marsupial opossum (Monodelphis domestica) and a eutherian rodent (Mesocricetus auratus) species under identical conditions, and directly compared BMR and basal proton leak. We confirmed an approximately 40 per cent lower mass specific BMR in the opossum although its proton leak was significantly higher (approx. 60%). We demonstrate that the increase in BMR during eutherian evolution is not based on a general increase in the mitochondrial proton leak, although there is a similar allometric relationship of proton leak and BMR within mammalian groups. The difference in proton leak between endothermic groups may assist in elucidating distinct metabolic and habitat requirements that have evolved during mammalian divergence.

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“…The use of energy density is justified because in the metabolic processes ATP cannot be supplied from outside but must be synthesized within the organism (within the cells). The efficient use of substrates by cells depends on the presence of an adequate quantity of mitochondria as power house [26] and secondly on adequate supply of fuels and oxygen. The fuels, which are directly related to the available energy E, are contained inside the organism but the oxygen flux is supplied by outside the organism.…”

Section: Hypotheses and Main Relationsmentioning

confidence: 99%

Non-universal interspecific allometric scaling of metabolism

Silva¹,

Barbosa²

2009

Braz. J. Phys.

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We extend a previously theory for the interspecific allometric scaling developed in a d + 1-dimensional space of metabolic states. The time, which is characteristic of all biological processes, is included as an extra dimension to d biological lengths. The different metabolic rates, such as basal (BMR) and maximum (MMR), are described by supposing that the biological lengths and time are related by different transport processes of energy and mass. We consider that the metabolic rates of animals are controlled by three main transport processes: convection, diffusion and anomalous diffusion. Different transport mechanisms are related to different metabolic states, with its own values for allometric exponents. In d = 3, we obtain that the exponent b of BMR is b = 0.71, and that the aerobic sustained MMR upper value of the exponent is b = 0.86 (best empirical values for mammals: b = 0.69(2) and b = 0.87(3)). The 3/4-law appears as an upper limit of BMR. The MMR scaling in different conditions, other exponents related to BMR and MMR, and the metabolism of unicellular organisms are also discussed.

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Body mass dependence of H+ leak in mitochondria and its relevance to metabolic rate

Cited by 240 publications

References 18 publications

Cardiac Basal Metabolism.

Cardiac Basal Metabolism.

Phylogenetic differences of mammalian basal metabolic rate are not explained by mitochondrial basal proton leak

Non-universal interspecific allometric scaling of metabolism

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