Alanine and glutamine kinetics at rest and during exercise in humans.
Alanine and glutamine kinetics at rest and during exercise in humans.
复制标题
人类休息和运动期间的丙氨酸和谷氨酰胺动力学。
DOI：
10.1097/00005768-199807000-00005
复制
发表时间：
1998
影响因子：
4.1
通讯作者：
Wolfe,RR
中科院分区：
文献类型：
--
作者：
Williams,BD;Chinkes,DL;Wolfe,RR
目的本研究的目的是在中等强度的运动过程中定量丙氨酸和谷氨酰胺的动力学，以确定丙氨酸和谷氨酰胺通量的总和。方法使用示踪剂方法定量6名正常志愿者（25+/-2岁，68 ± 2.5 kg，最大摄氧量43 ± 2.4 mL。min-1。kg-1;平均值+/-SE）。运动开始后1 d和10-15 min分别给予2 H5-谷氨酰胺和3- 13 C-丙氨酸单次注射（N = 3）或预充恒定输注（N= 3）。血浆富集衰减曲线和平台富集被用来估计丙氨酸和谷氨酰胺kinetic. ResultsWhile丙氨酸Ra增加显着从休息到运动（5.72+/-0.31比13.5+/-1.9 mumol。min-1。kg-1; P< 0.01），谷氨酰胺Ra在运动中没有显著改变（6.11+/-0.44和6.40+/-0.69 mumol. min-1。kg-1，分别在休息和运动期间）。丙氨酸和谷氨酰胺的总通量从17.93 ± 0.88增加到25.98 ± 3.04（P< 0.05）。结论由于大多数肌肉氨基氮以丙氨酸和谷氨酰胺的形式释放，这些发现提供了强有力的证据表明，在运动过程中，从肌肉到肝脏的氨基氮输送增加。此外，它似乎是丙氨酸，而不是谷氨酰胺，是主要的N载体参与的N从肌肉转移到肝脏在中等强度的运动。
PurposeThe purpose of this study was to quantify both alanine and glutamine kinetics during exercise of moderate intensity to determine the sum total of alanine and glutamine flux.MethodsTracer methods were used to quantify alanine and glutamine rates of appearance (Ra) in plasma at rest and during 180 min of approximately 45% VO2max treadmill exercise in six normal volunteers (25+/-2 yr, 68+/-2.5 kg, VO2max 43+/-2.4 mL. min-1. kg-1; means+/-SE). Bolus injections (N= 3) or primed-constant infusions (N= 3) of 2H5-glutamine and 3-13C-alanine were given at rest on 1 d and 10-15 min after the onset of exercise on a separate day less than 2 wk later. Plasma enrichment decay curves and plateau enrichments were used to estimate alanine and glutamine kinetics.ResultsWhereas alanine Ra increased significantly from rest to exercise (5.72+/-0.31 vs 13.5+/-1.9 mumol. min-1. kg-1, respectively; P< 0.01), glutamine Ra was not significantly altered by exercise (6.11+/-0.44 and 6.40+/-0.69 mumol. min-1. kg-1 at rest and during exercise, respectively). The total of alanine and glutamine flux increased from 17.93+/-0.88 to 25.98+/-3.04 (P< 0.05).ConclusionsSince most muscle amino-N is released as alanine and glutamine, these findings provide strong evidence that amino-N delivery from muscle to the liver is increased during exercise. In addition, it appears that alanine, rather than glutamine, is the predominant N carrier involved in the transfer of N from muscle to the liver during moderate intensity exercise.