Norman B, Sollevi A, Kaijser L, Jansson E
Department of Clinical Physiology, Karolinska Hospital, Stockholm, Sweden.
Clin Physiol. 1987 Dec;7(6):503-10. doi: 10.1111/j.1475-097x.1987.tb00192.x.
To study changes in muscle energy state during prolonged exercise, especially in relation to fatigue, muscle biopsies were obtained from seven healthy males working until exhaustion on a cycle ergometer at 68% (63-74%) of their maximal oxygen uptake. Biopsies were taken at rest, after 15 and 45 min of exercise and at exhaustion, and analysed for ATP, ADP, AMP, inosine monophosphate (IMP) and hypoxanthine content by high performance liquid chromatography (HPLC), and for creatine phosphate (CP), lactate and glycogen by enzymatic fluorometric techniques. Glycogen content at exhaustion was approximately 30% of the pre-exercise level. The CP content decreased steeply during the first 15 min of exercise (P less than 0.01) and continued to decrease during the rest of the exercise period (P less than 0.05). Pronounced increases in contents of IMP (64% P less than 0.001) and hypoxanthine (69%, P less than 0.05) were found when exhaustion was approaching. Furthermore, energy charge [EC; (ATP + 0.5 ADP)/(ATP + ADP + AMP)] was decreased at exhaustion (P less than 0.05). The increases in IMP and hypoxanthine which occurred when exhaustion was approaching during prolonged submaximal exercise together with the decrease in EC during this phase of exercise suggest a failure of the exercising skeletal muscle to regenerate ATP at exhaustion.
为研究长时间运动期间肌肉能量状态的变化，尤其是与疲劳相关的变化，从七名健康男性身上获取了肌肉活检样本。这些男性在功率自行车上以其最大摄氧量的68%（63 - 74%）进行运动直至力竭。在休息时、运动15分钟和45分钟后以及力竭时进行活检，并通过高效液相色谱法（HPLC）分析三磷酸腺苷（ATP）、二磷酸腺苷（ADP）、一磷酸腺苷（AMP）、肌苷一磷酸（IMP）和次黄嘌呤的含量，通过酶荧光技术分析磷酸肌酸（CP）、乳酸和糖原的含量。力竭时的糖原含量约为运动前水平的30%。CP含量在运动的前15分钟急剧下降（P < 0.01），并在运动的剩余时间内持续下降（P < 0.05）。当接近力竭时，发现IMP含量显著增加（64%，P < 0.001），次黄嘌呤含量增加（69%，P < 0.05）。此外，力竭时能量电荷[EC；(ATP + 0.5 ADP)/(ATP + ADP + AMP)]下降（P < 0.05）。长时间次最大运动接近力竭时IMP和次黄嘌呤的增加以及运动此阶段EC的下降表明，运动的骨骼肌在力竭时无法再生ATP。
