Op 't Eijnde B, Ursø B, Richter E A, Greenhaff P L, Hespel P
Faculty of Physical Education and Physiotherapy, Exercise Physiology and Biomechanics Laboratory, Katholieke Universiteit Leuven, Belgium.
Diabetes. 2001 Jan;50(1):18-23. doi: 10.2337/diabetes.50.1.18.
The purpose of this study was to investigate the effect of oral creatine supplementation on muscle GLUT4 protein content and total creatine and glycogen content during muscle disuse and subsequent training. A double-blind placebo-controlled trial was performed with 22 young healthy volunteers. The right leg of each subject was immobilized using a cast for 2 weeks, after which subjects participated in a 10-week heavy resistance training program involving the knee-extensor muscles (three sessions per week). Half of the subjects received creatine monohydrate supplements (20 g daily during the immobilization period and 15 and 5 g daily during the first 3 and the last 7 weeks of rehabilitation training, respectively), whereas the other 11 subjects ingested placebo (maltodextrine). Muscle GLUT4 protein content and glycogen and total creatine concentrations were assayed in needle biopsy samples from the vastus lateralis muscle before and after immobilization and after 3 and 10 weeks of training. Immobilization decreased GLUT4 in the placebo group (-20%, P < 0.05), but not in the creatine group (+9% NS). Glycogen and total creatine were unchanged in both groups during the immobilization period. In the placebo group, during training, GLUT4 was normalized, and glycogen and total creatine were stable. Conversely, in the creatine group, GLUT4 increased by approximately 40% (P < 0.05) during rehabilitation. Muscle glycogen and total creatine levels were higher in the creatine group after 3 weeks of rehabilitation (P < 0.05), but not after 10 weeks of rehabilitation. We concluded that 1) oral creatine supplementation offsets the decline in muscle GLUT4 protein content that occurs during immobilization, and 2) oral creatine supplementation increases GLUT4 protein content during subsequent rehabilitation training in healthy subjects.
本研究旨在探讨口服补充肌酸对肌肉废用及后续训练期间肌肉葡萄糖转运蛋白4（GLUT4）含量、总肌酸和糖原含量的影响。对22名年轻健康志愿者进行了一项双盲安慰剂对照试验。每位受试者的右腿用石膏固定2周，之后受试者参加一项为期10周的涉及膝伸肌的高强度抗阻训练计划（每周三次）。一半受试者服用一水肌酸补充剂（固定期每日20 g，康复训练的前3周和最后7周分别每日15 g和5 g），而另外11名受试者摄入安慰剂（麦芽糊精）。在固定前后以及训练3周和10周后，从股外侧肌的针吸活检样本中检测肌肉GLUT4蛋白含量、糖原和总肌酸浓度。固定使安慰剂组的GLUT4降低（-20%，P<0.05），但肌酸组未降低（+9%，无显著性差异）。固定期两组的糖原和总肌酸均无变化。在安慰剂组中，训练期间GLUT4恢复正常，糖原和总肌酸保持稳定。相反，在肌酸组中，康复期间GLUT4增加了约40%（P<0.05）。康复3周后，肌酸组的肌肉糖原和总肌酸水平较高（P<0.05），但康复10周后则不然。我们得出结论：1）口服补充肌酸可抵消固定期间发生的肌肉GLUT4蛋白含量下降；2）口服补充肌酸可增加健康受试者后续康复训练期间的GLUT4蛋白含量。
