James J H, Fang C H, Schrantz S J, Hasselgren P O, Paul R J, Fischer J E
Department of Surgery, University of Cincinnati, Ohio 45267, USA.
J Clin Invest. 1996 Nov 15;98(10):2388-97. doi: 10.1172/JCI119052.
Although a linkage between aerobic glycolysis and sodium-potassium transport has been demonstrated in diaphragm, vascular smooth muscle, and other cells, it is not known whether this linkage occurs in skeletal muscle generally. Metabolism of intact hind-leg muscles from young rats was studied in vitro under aerobic incubation conditions. When sodium influx into rat extensor digitorum longus (EDL) and soleus muscles was facilitated by the sodium ionophore monensin, muscle weight gain and production of lactate and alanine were markedly stimulated in a dose-dependent manner. Although lactate production rose in both muscles, it was more pronounced in EDL than in soleus. Monensin-induced lactate production was inhibited by ouabain or by incubation in sodium-free medium. Preincubation in potassium-free medium followed by potassium re-addition also stimulated ouabain-inhibitable lactate release. Replacement of glucose in the incubation medium with pyruvate abolished monensin-induced lactate production but exacerbated monensin-induced weight gain. Muscles from septic or endotoxin-treated rats exhibited an increased rate of lactate production in vitro that was partially inhibited by ouabain. Increases muscle lactate production in sepsis may reflect linked increases in activity of the Na+, K+-ATPase, consumption of ATP and stimulation of aerobic glycolysis.
虽然有氧糖酵解与钠钾转运之间的联系已在膈肌、血管平滑肌及其他细胞中得到证实，但尚不清楚这种联系是否普遍存在于骨骼肌中。在有氧培养条件下，对幼鼠完整后肢肌肉的代谢进行了体外研究。当用钠离子载体莫能菌素促进钠离子流入大鼠趾长伸肌（EDL）和比目鱼肌时，肌肉重量增加以及乳酸和丙氨酸的生成受到显著刺激，且呈剂量依赖性。虽然两块肌肉中的乳酸生成均增加，但在EDL中比在比目鱼肌中更明显。哇巴因或在无钠培养基中孵育可抑制莫能菌素诱导的乳酸生成。在无钾培养基中预孵育后再添加钾也会刺激哇巴因可抑制的乳酸释放。用丙酮酸替代孵育培养基中的葡萄糖可消除莫能菌素诱导的乳酸生成，但会加剧莫能菌素诱导的重量增加。来自脓毒症或内毒素处理大鼠的肌肉在体外表现出乳酸生成速率增加，且部分受到哇巴因抑制。脓毒症中肌肉乳酸生成增加可能反映了Na +，K + -ATP酶活性、ATP消耗以及有氧糖酵解刺激的相关增加。
