Effects of starvation and exercise on concentrations of citrate, hexose phosphates and glycogen in skeletal muscle and heart. Evidence for selective operation of the glucose-fatty acid cycle.
Effects of starvation and exercise on concentrations of citrate, hexose phosphates and glycogen in skeletal muscle and heart. Evidence for selective operation of the glucose-fatty acid cycle.
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DOI：
10.1042/bj2320585
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发表时间：
1985-12
期刊：
影响因子：
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通讯作者：
A. Zorzano;Thomas W. Balon;Linda J. Brady;P. Rivera;Lawrence P. Garetto;J. C. Young;Michael N. Goodman;Neil B. Ruderman
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文献类型：
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作者：
A. Zorzano;Thomas W. Balon;Linda J. Brady;P. Rivera;Lawrence P. Garetto;J. C. Young;Michael N. Goodman;Neil B. Ruderman
在血浆非酯化脂肪酸和酮体生理性增加的条件下，测定骨骼肌和心脏中柠檬酸盐、己糖磷酸盐和糖原的浓度。目的是确定在什么条件下葡萄糖-脂肪酸循环可能在体内骨骼肌中起作用。与其他人的发现一致，饥饿增加了心脏中糖原、柠檬酸盐和果糖6-磷酸/果糖1，6-二磷酸的浓度，表明循环是有效的。相反，它减少了糖原，对比目鱼肌中柠檬酸盐的浓度或果糖6-磷酸/果糖1，6-二磷酸的比例没有影响，比目鱼肌是一种慢收缩的红色肌肉，其中葡萄糖-脂肪酸循环已在体外得到证实。在进食的大鼠中，中等强度的运动导致比目鱼肌和腓肠肌红色部分的糖原消耗，但不是在心脏。在饥饿的大鼠中，同样的运动对骨骼肌中已经减少的糖原含量没有影响，但它使心脏糖原减少了25- 30%。运动后，柠檬酸和果糖6-磷酸/果糖1，6-二磷酸的比例增加饥饿大鼠比目鱼肌。在喂食大鼠中未观察到显著变化。这些数据表明，在静息状态下，葡萄糖-脂肪酸循环在饥饿大鼠的心脏中进行，但在比目鱼肌中不进行。相反，比目鱼肌中的代谢产物谱与运动后恢复期间饥饿大鼠中葡萄糖-脂肪酸循环的激活一致。这个周期是否在运动过程中运行尚不清楚。
Concentrations of citrate, hexose phosphates and glycogen were measured in skeletal muscle and heart under conditions in which plasma non-esterified fatty acids and ketone bodies were physiologically increased. The aim was to determine under what conditions the glucose-fatty acid cycle might operative in skeletal muscle in vivo. In keeping with the findings of others, starvation increased the concentrations of glycogen, citrate and the fructose 6-phosphate/fructose 1,6-bisphosphate ratio in heart, indicating that the cycle was operative. In contrast, it decreased glycogen and had no effect on the concentration of citrate or the fructose 6-phosphate/fructose 1,6-bisphosphate ratio in the soleus, a slow-twitch red muscle in which the glucose-fatty acid cycle has been demonstrated in vitro. In fed rats, exercise of moderate intensity caused glycogen depletion in the soleus and red portion of gastrocnemius muscle, but not in heart. In starved rats the same exercise had no effect on the already diminished glycogen contents in skeletal muscle, but it decreased cardiac glycogen by 25-30%. After exercise, citrate and the fructose 6-phosphate/fructose 1,6-bisphosphate ratio were increased in the soleus of the starved rat. Significant changes were not observed in fed rats. The data suggest that in the resting state the glucose-fatty acid cycle operates in the heart, but not in the soleus muscle, of a starved rat. In contrast, the metabolite profile in the soleus was consistent with activation of the glucose-fatty acid cycle in the starved rat during the recovery period after exercise. Whether the cycle operates during exercise itself is unclear.