Muscle metabolic, enzymatic and transporter responses to a session of prolonged cycling

作者：Green H J^*; Duhamel T A; Smith I C; Rich S M; Thomas M M; Ouyang J; Yau J E

来源：European Journal of Applied Physiology, 2011, 111(5): 827-837.

DOI：10.1007/s00421-010-1709-y

• Exercise
• Acute
• Lasting effects
• Metabolism
• Enzymes
• Glucose and monocarboxylate transporters
• Substrate
• Glycogen

A single session of prolonged work was employed to investigate changes in selected metabolic, transporter and enzymatic properties in muscle. Ten active but untrained volunteers (weight = 73.9 +/- A 4.2 kg) with a peak aerobic power (VO(2peak)) of 2.95 +/- A 0.27 l min(-1), cycled for 2 h at 62 +/- A 1.3% (VO(2peak)) Tissue extraction from the vastus lateralis occurred prior to (E1-Pre) and following (E1-Post) exercise and on 3 consecutive days of recovery (R1, R2, R3). The exercise resulted in decreases (P < 0.05) in ATP (-9.3%) and creatine phosphate (-49%) and increases in lactate (+100%), calculated free ADP (+253%) and free AMP (+1,207%), all of which recovered to E1-Pre by R1. Glycogen concentration, which was depressed (P < 0.05) by 75% at E1-Post, did not recover until R3. Compared to E1-Pre, the cycling also resulted in decreases (P < 0.05) in the activities of cytochrome c oxidase, phosphorylase, and hexokinase but not in citrate synthase (CS) or 3-hydroxy-CoA dehydrogenase at E1-Post. With the exception of CS, which was elevated (P < 0.05) at R3, all enzyme activities were not different from E1-Pre during recovery. For the glucose (GLUT1, GLUT4) and monocarboxylate (MCT1, MCT4) transporters, changes in expression levels (P < 0.05) were only observed for GLUT1 at R1 (+42%) and R3 (+33%). It is concluded that the metabolic stress produced by prolonged exercise is reversed by 1 day of recovery. One day of exercise also resulted in a potential upregulation in the citric acid cycle and glucose transport capabilities, adaptations which are expressed at variable recovery durations.

• 出版日期2011-5