Carraro F, Hartl W H, Stuart C A, Layman D K, Jahoor F, Wolfe R R
Metabolism Unit, Shriners Burns Institute, Galveston, Texas.
Am J Physiol. 1990 May;258(5 Pt 1):E821-31. doi: 10.1152/ajpendo.1990.258.5.E821.
The effect of 4 h of exercise at 40% of maximal oxygen consumption (VO2 max) on protein metabolism was assessed in normal volunteers maintained on a diet containing 42 kcal.kg-1.day-1 and either 0.9 or 2.5 g protein.kg-1.day-1. Primed constant infusions of [1,2-13C]-leucine and [15N]glycine enabled the quantitation of whole body protein turnover and also the fractional synthetic rates (FSR) of albumin, fibrinogen, and fibronectin. In subjects who did not exercise, the fractional synthetic rates (%/day) on normal and high-protein intakes, respectively, were as follows: albumin, 10 +/- 1 and 9 +/- 1; fibrinogen, 21 +/- 3 and 18 +/- 1; and fibronectin, 31 +/- 3 and 34 +/- 3. Neither exercise nor recovery had an effect of whole body protein turnover or on albumin FSR, but the FSR of fibronectin was significantly elevated at the end of exercise, and fibrinogen was significantly elevated in recovery. Dietary protein intake had no major effect on the response to exercise. Thus, in response to exercise, there is a stimulation of the synthesis of some acute phase proteins, which may be a mechanism whereby nitrogen resulting from muscle protein breakdown is spared.
在摄入含42千卡·千克⁻¹·天⁻¹热量且蛋白质含量分别为0.9克·千克⁻¹·天⁻¹或2.5克·千克⁻¹·天⁻¹饮食的正常志愿者中，评估了以最大耗氧量（VO₂ max）的40%进行4小时运动对蛋白质代谢的影响。通过对[1,2-¹³C] - 亮氨酸和[¹⁵N] - 甘氨酸进行预充式持续输注，能够对全身蛋白质周转率以及白蛋白、纤维蛋白原和纤连蛋白的分数合成率（FSR）进行定量分析。在未运动的受试者中，正常蛋白质摄入量和高蛋白质摄入量时的分数合成率（%/天）分别如下：白蛋白，10±1和9±1；纤维蛋白原，21±3和18±1；纤连蛋白，31±3和34±3。运动和恢复过程均未对全身蛋白质周转率或白蛋白FSR产生影响，但运动结束时纤连蛋白的FSR显著升高，恢复过程中纤维蛋白原显著升高。饮食蛋白质摄入量对运动反应没有主要影响。因此，运动时会刺激一些急性期蛋白的合成，这可能是一种机制，通过该机制可节省肌肉蛋白分解产生的氮。
