Body mass dependence of oxidative phosphorylation efficiency in liver mitochondria from mammals.

In eukaryotes, the performances of an organism are dependent on body mass and chemically supported by the mitochondrial production of ATP. Although the relationship between body mass and mitochondrial oxygen consumption is well described, the allometry of the transduction efficiency from oxygen to ATP production (ATP/O) is still poorly understood. Using a comparative approach, we investigated the oxygen consumption and ATP production of liver mitochondria from twelve species of mammals ranging from 5 g to 600 kg. We found that both oxygen consumption and ATP production are mass dependent but not the ATP/O at the maximal phosphorylating state. The results also showed that for sub-maximal phosphorylating states the ATP/O value positively correlated with body mass, irrespective of the metabolic intensity. This result contrasts with previous data obtained in mammalian muscles, suggesting a tissue-dependence of the body mass effect on mitochondrial efficiency.