Welle S, Thornton C A
Department of Medicine, University of Rochester, New York 14620, USA.
Am J Physiol. 1998 Apr;274(4):E677-83. doi: 10.1152/ajpendo.1998.274.4.E677.
This study tested the hypothesis that increasing the protein content of isocaloric meals increases the rate of myofibrillar synthesis in muscle of healthy subjects over 60 yr old and enhances the stimulation of myofibrillar synthesis induced by resistance exercise. Myofibrillar synthesis of sedentary and exercised quadriceps muscle was determined by incorporation of L-[1-13C]leucine. During the tracer infusion, subjects consumed meals with a low (7% of energy, n = 6)-, normal (14%, n = 6)-, or high (28%, n = 6)-protein content. In sedentary muscle, the mean (+/- SE) myofibrillar synthesis was 1.56 +/- 0.13%/day in the low-protein group, 1.73 +/- 0.11 %/day in the normal-protein group, and 1.76 +/- 0.10%/day in the high-protein group (P = 0.42). Myofibrillar synthesis was faster in exercised muscle (mean 27%, P < 10(-6) in all groups (2.10 +/- 0.14%/day in low protein; 2.18 +/- 0.10%/day in normal protein; 2.11 +/- 0.09%/day in high protein; P = 0.84). The stimulation of myofibrillar synthesis by exercise was not significantly different among low-protein [0.54 +/- 0.12%/day (37 +/- 9%)], normal-protein [0.46 +/- 0.08%/day (28 +/- 5%)], and high-protein groups [0.34 +/- 0.04%/day (20 +/- 3%); P = 0.31]. We conclude that high-protein meals do not enhance the stimulation of myofibrillar protein synthesis induced by resistance exercise.
增加等热量餐中的蛋白质含量，会提高60岁以上健康受试者肌肉中肌原纤维的合成速率，并增强抗阻运动对肌原纤维合成的刺激作用。通过L-[1-13C]亮氨酸掺入法测定久坐不动和进行过运动的股四头肌的肌原纤维合成情况。在示踪剂输注期间，受试者食用蛋白质含量低（占能量的7%，n = 6）、正常（14%，n = 6）或高（28%，n = 6）的餐食。在久坐不动的肌肉中，低蛋白组的肌原纤维合成平均（±标准误）为1.56±0.13%/天，正常蛋白组为1.73±0.11%/天，高蛋白组为1.76±0.10%/天（P = 0.42）。所有组中，运动肌肉的肌原纤维合成速度更快（平均快27%，P < 10(-6)）（低蛋白组为2.10±0.14%/天；正常蛋白组为2.18±0.10%/天；高蛋白组为2.11±0.09%/天；P = 0.84）。低蛋白组[0.54±0.12%/天（37±9%）]、正常蛋白组[0.46±0.08%/天（28±5%）]和高蛋白组[0.34±0.04%/天（20±3%）]中，运动对肌原纤维合成的刺激作用无显著差异（P = 0.31）。我们得出结论，高蛋白餐食不会增强抗阻运动对肌原纤维蛋白合成的刺激作用。
