Richter E A, Sonne B, Mikines K J, Ploug T, Galbo H
Eur J Appl Physiol Occup Physiol. 1984;52(3):346-50. doi: 10.1007/BF01015225.
We have previously found that during exercise net muscle glycogen breakdown is impaired in adrenodemedullated rats, as compared with controls. The present study was carried out to elucidate whether, in rats with deficiencies of the sympatho-adrenal system, diminished exercise-induced glycogenolysis in skeletal muscle was accompanied by increased breakdown of triglyceride and/or protein. Thus, the effect of exhausting swimming and of running on concentrations of glycogen, protein, and triglyceride in skeletal muscle and liver were studied in rats with and without deficiencies of the sympatho-adrenal system. In control rats, both swimming and running decreased the concentration of glycogen in fast-twitch red and slow-twitch red muscle whereas concentrations of protein and triglyceride did not decrease. In the liver, swimming depleted glycogen stores but protein and triglyceride concentrations did not decrease. In exercising rats, muscle glycogen breakdown was impaired by adrenodemedullation and restored by infusion of epinephrine. However, impaired glycogen breakdown during exercise was not accompanied by a significant net breakdown of protein or triglyceride. Surgical sympathectomy of the muscles did not influence muscle substrate concentrations. The results indicate that when glycogenolysis in exercising muscle is impeded by adrenodemedullation no compensatory increase in breakdown of triglyceride and protein in muscle or liver takes place. Thus, indirect evidence suggests that, in exercising adrenodemedullated rats, fatty acids from adipose tissue were burnt instead of muscle glycogen.
我们之前发现，与对照组相比，在运动过程中，去肾上腺髓质大鼠的净肌肉糖原分解受损。本研究旨在阐明，在交感-肾上腺系统功能不足的大鼠中，骨骼肌运动诱导的糖原分解减少是否伴随着甘油三酯和/或蛋白质分解增加。因此，我们研究了有无交感-肾上腺系统功能不足的大鼠进行力竭游泳和跑步后，骨骼肌和肝脏中糖原、蛋白质和甘油三酯的浓度变化。在对照大鼠中，游泳和跑步均降低了快肌红肌和慢肌红肌中的糖原浓度，而蛋白质和甘油三酯浓度未降低。在肝脏中，游泳耗尽了糖原储备，但蛋白质和甘油三酯浓度未降低。在运动大鼠中，去肾上腺髓质会损害肌肉糖原分解，而肾上腺素输注可恢复糖原分解。然而，运动期间受损的糖原分解并未伴随着蛋白质或甘油三酯的显著净分解。对肌肉进行手术交感神经切除并不影响肌肉底物浓度。结果表明，当去肾上腺髓质导致运动肌肉中的糖原分解受到阻碍时，肌肉或肝脏中甘油三酯和蛋白质的分解不会出现代偿性增加。因此，间接证据表明，在运动的去肾上腺髓质大鼠中，脂肪组织中的脂肪酸被燃烧，而非肌肉糖原。
