Mazzulla Michael, Parel Justin T, Beals Joseph W, VAN Vliet Stephan, Abou Sawan Sidney, West Daniel W D, Paluska Scott A, Ulanov Alexander V, Moore Daniel R, Burd Nicholas A
1Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, CANADA; 2Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL; 3Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Champaign, IL; 4Department of Family Medicine, University of Illinois at Urbana-Champaign, Champaign, IL; and 5Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Champaign, IL.
Med Sci Sports Exerc. 2017 Dec;49(12):2585-2592. doi: 10.1249/MSS.0000000000001394.
Endurance exercise increases indices of small intestinal damage and leucine oxidation, which may attenuate dietary amino acid appearance and postprandial leucine balance during postexercise recovery. Therefore, the purpose of this study was to examine the effect of an acute bout of endurance exercise on postprandial leucine kinetics and net leucine balance.
In a crossover design, seven trained young men (age = 25.6 ± 2.3 yr; V˙O2peak = 61.4 ± 2.9 mL·kg·min; mean ± SEM) received a primed constant infusion of L-[1-C]leucine before and after ingesting a mixed macronutrient meal containing 18 g whole egg protein intrinsically labeled with L-[5,5,5-H3]leucine, 17 g fat, and 60 g carbohydrate at rest and after 60 min of treadmill running at 70% V˙O2peak.
Plasma intestinal fatty acid binding protein concentrations and leucine oxidation both increased (P < 0.01) to peaks that were ~2.5-fold above baseline values during exercise with a concomitant decrease (P < 0.01) in nonoxidative leucine disposal. Meal ingestion attenuated (P < 0.01) endogenous leucine rates of appearance at rest and after exercise. There were no differences (both, P > 0.05) in dietary leucine appearance rates or in the amount of dietary protein-derived leucine that appeared into circulation over the 5-h postprandial period at rest and after exercise (62% ± 2% and 63% ± 2%, respectively). Leucine balance over the 5-h postprandial period was positive (P < 0.01) in both conditions but was negative (P < 0.01) during the exercise trial after accounting for exercise-induced leucine oxidation.
We demonstrate that endurance exercise does not modulate dietary leucine availability from a mixed meal but attenuates postprandial whole-body leucine balance in trained young men.
耐力运动可增加小肠损伤指标和亮氨酸氧化，这可能会减弱运动后恢复期间膳食氨基酸的出现及餐后亮氨酸平衡。因此，本研究的目的是检验一次急性耐力运动对餐后亮氨酸动力学和净亮氨酸平衡的影响。
采用交叉设计，七名训练有素的年轻男性（年龄=25.6±2.3岁；峰值摄氧量=61.4±2.9 mL·kg·min；均值±标准误）在静息状态下以及在以70%峰值摄氧量进行60分钟跑步机跑步后，摄入含有18克用L-[5,5,5-H3]亮氨酸进行内在标记的全蛋蛋白、17克脂肪和60克碳水化合物的混合常量营养素餐前后，接受L-[1-C]亮氨酸的预充常量输注。
血浆肠脂肪酸结合蛋白浓度和亮氨酸氧化均增加（P<0.01），在运动期间达到比基线值高约2.5倍的峰值，同时非氧化亮氨酸处置减少（P<0.01）。进餐减弱了（P<0.01）静息状态下和运动后的内源性亮氨酸出现率。在静息状态下和运动后，餐后5小时膳食亮氨酸出现率或进入循环的膳食蛋白质衍生亮氨酸量均无差异（两者，P>0.05）（分别为62%±2%和63%±2%）。在两种情况下，餐后5小时的亮氨酸平衡均为正值（P<0.01），但在考虑运动诱导的亮氨酸氧化后，运动试验期间为负值（P<0.01）。
我们证明，耐力运动不会调节混合餐中膳食亮氨酸的可用性，但会减弱训练有素的年轻男性的餐后全身亮氨酸平衡。
