Price T B, Laurent D, Petersen K F, Rothman D L, Shulman G I
Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
J Appl Physiol (1985). 2000 Feb;88(2):698-704. doi: 10.1152/jappl.2000.88.2.698.
This study compared muscle glycogen recovery after depletion of approximately 50 mmol/l (DeltaGly) from normal (Nor) resting levels (63.2 +/- 2.8 mmol/l) with recovery after depletion of approximately 50 mmol/l from a glycogen-loaded (GL) state (99.3 +/- 4.0 mmol/l) in 12 healthy, untrained subjects (5 men, 7 women). To glycogen load, a 7-day carbohydrate-loading protocol increased muscle glycogen 1.6 +/- 0.2-fold (P < or = 0.01). GL subjects then performed plantar flexion (single-leg toe raises) at 50 +/- 3% of maximum voluntary contraction (MVC) to yield DeltaGly = 48.0 +/- 1.3 mmol/l. The Nor trial, performed on a separate occasion, yielded DeltaGly = 47.5 +/- 4.5 mmol/l. Interleaved natural abundance (13)C-(31)P-NMR spectra were acquired and quantified before exercise and during 5 h of recovery immediately after exercise. During the initial 15 min after exercise, glycogen recovery in the GL trial was rapid (32.9 +/- 8.9 mmol. l(-1). h(-1)) compared with the Nor trial (15.9 +/- 6.9 mmol. l(-1). h(-1)). During the next 45 min, GL glycogen synthesis was not as rapid as in the Nor trial (0.9 +/- 2.5 mmol. l(-1). h(-1) for GL; 14.7 +/- 3.0 mmol. l(-1). h(-1) for Nor; P < or = 0.005) despite similar glucose 6-phosphate levels. During extended recovery (60-300 min), reduced GL recovery rates continued (1.3 +/- 0.5 mmol. l(-1). h(-1) for GL; 3.9 +/- 0.3 mmol. l(-1). h(-1) for Nor; P < or = 0.001). We conclude that glycogen recovery from heavy exercise is controlled primarily by the remaining postexercise glycogen concentration, with only a transient synthesis period when glycogen levels are not severely reduced.
本研究比较了12名健康的未经训练的受试者（5名男性，7名女性）在从正常（Nor）静息水平（63.2±2.8 mmol/l）消耗约50 mmol/l（ΔGly）后肌肉糖原的恢复情况，与从糖原负荷（GL）状态（99.3±4.0 mmol/l）消耗约50 mmol/l后的恢复情况。为了使糖原负荷增加，采用了为期7天的碳水化合物负荷方案，使肌肉糖原增加了1.6±0.2倍（P≤0.01）。然后，GL组受试者以最大自主收缩（MVC）的50±3%进行跖屈（单腿提踵），以使ΔGly = 48.0±1.3 mmol/l。在另一个时间进行的Nor试验中，ΔGly = 47.5±4.5 mmol/l。在运动前以及运动后立即恢复的5小时内，采集并定量了交错式自然丰度（13）C-（31）P-NMR光谱。在运动后的最初15分钟内，GL试验中的糖原恢复速度较快（32.9±8.9 mmol·l-1·h-1），而Nor试验中的恢复速度为（15.9±6.9 mmol·l-1·h-1）。在接下来的45分钟内，尽管6-磷酸葡萄糖水平相似，但GL组的糖原合成速度不如Nor试验快（GL组为0.9±2.5 mmol·l-1·h-1；Nor组为l4.7±3.0 mmol·l-1·h-1；P≤0.005）。在延长恢复期间（60 - 300分钟），GL组的恢复速度持续降低（GL组为1.3±0.5 mmol·l-1·h-1；Nor组为l3.9±0.3 mmol·l-1·h-1；P≤0.001）。我们得出结论，剧烈运动后的糖原恢复主要受运动后剩余糖原浓度的控制，只有在糖原水平未严重降低时才有一个短暂的合成期。
