Goodenough R D, Royle G T, Nadel E R, Wolfe M H, Wolfe R R
J Appl Physiol Respir Environ Exerc Physiol. 1982 Aug;53(2):367-72. doi: 10.1152/jappl.1982.53.2.367.
Four healthy males voluntarily underwent acute cold exposure at 10 degrees C. Metabolic rate doubled for the 100-min exposure. [1-13C]leucine and [15N2]urea were used as tracers of protein metabolism via a primed constant infusion. Total and plasma transported leucine oxidation approximately doubled, but the oxidation of leucine derived from protein in the tissue where oxidation occurred ("intracellular oxidation") did not change as it did when the same subjects underwent mild exercise. Rate of appearance of urea and leucine in plasma were not significantly different between control and cold. Although the rate of protein synthesis calculated from the leucine data did not change, the rate of catabolism increased. Net protein catabolism based on the urea data agreed well with the leucine data at rest but did not exhibit a significant increase during exposure. However, net protein catabolism based on the leucine data did increase significantly during acute cold exposure. Further, there appears to be a qualitative difference in the protein catabolism associated with the voluntary muscular activity of exercise and muscular shivering aimed at thermogenesis.
四名健康男性自愿在10摄氏度下接受急性冷暴露。在100分钟的暴露期间，代谢率增加了一倍。通过初始恒速输注，使用[1-13C]亮氨酸和[15N2]尿素作为蛋白质代谢的示踪剂。总的和血浆转运的亮氨酸氧化量大约增加了一倍，但在发生氧化的组织中（“细胞内氧化”）由蛋白质衍生的亮氨酸氧化量并未改变，而当相同受试者进行轻度运动时该氧化量是变化的。对照组和冷暴露组之间血浆中尿素和亮氨酸的出现率没有显著差异。尽管根据亮氨酸数据计算的蛋白质合成速率没有变化，但分解代谢速率增加。基于尿素数据的净蛋白质分解代谢在静息时与亮氨酸数据吻合良好，但在暴露期间没有显著增加。然而，基于亮氨酸数据的净蛋白质分解代谢在急性冷暴露期间确实显著增加。此外，与旨在产热的运动的自愿肌肉活动和肌肉颤抖相关的蛋白质分解代谢似乎存在质的差异。
