Porter R K, Brand M D
Department of Biochemistry, University of Cambridge, UK.
Nature. 1993 Apr 15;362(6421):628-30. doi: 10.1038/362628a0.
The standard metabolic rate of an animal is the rate of heat production under conditions that minimize known extra requirements for energy. In tissues and cells from aerobic organisms, energy expenditure can conveniently be measured as oxygen consumption. Measurements made using isolated rat hepatocytes have shown that a significant contribution to resting oxygen consumption (and hence heat production) is made by a futile cycle of proton pumping and proton leak across the mitochondrial inner membrane. Two important factors affecting standard metabolic rate, thyroid status and phylogeny, also affect the proton permeability. A third major factor affecting standard metabolic rate is body mass. Here we show that proton leak decreases with increasing body mass in mammals. We suggest that differences in proton leak may partly explain the differences in standard metabolic rate between mammals of different mass.
动物的标准代谢率是指在将已知额外能量需求降至最低的条件下的产热速率。在需氧生物的组织和细胞中，能量消耗可以方便地通过氧气消耗量来衡量。使用分离的大鼠肝细胞进行的测量表明，线粒体内膜上质子泵浦和质子泄漏的无效循环对静息氧气消耗（进而产热）有显著贡献。影响标准代谢率的两个重要因素，即甲状腺状态和系统发育，也会影响质子通透性。影响标准代谢率的第三个主要因素是体重。在此我们表明，在哺乳动物中，质子泄漏随体重增加而减少。我们认为，质子泄漏的差异可能部分解释了不同体重哺乳动物之间标准代谢率的差异。
