Department of Exercise Physiology, Faculty of Physical Education and Sport Science, Shahid Bahonar University of Kerman, Kerman, Iran.
J Physiol Biochem. 2013 Dec;69(4):865-77. doi: 10.1007/s13105-013-0263-6. Epub 2013 May 29.
We hypothesized that a part of therapeutic effects of endurance training on insulin resistance is mediated by increase in cardiac and skeletal muscle mitochondrial lactate transporter, monocarboxylate transporter 1 (MCT1). Therefore, we examined the effect of 7 weeks endurance training on the mRNA and protein expression of MCT1 and MCT4 and their chaperon, CD147, on both sarcolemmal and mitochondrial membrane, separately, in healthy and type 2 diabetic rats. Diabetes was induced by injection of low dose of streptozotocin and feeding with high-fat diet. Insulin resistance was confirmed by homeostasis model assessment-estimated insulin resistance index and accuracy of two membranes separation was confirmed by negative control markers (glucose transporter 1 and cytochrome c oxidase. Real-time PCR and western blotting were used for mRNA and protein expression, respectively. Diabetes dramatically reduced MCT1 and MCT4 mRNA and their expression on sarcolemmal membrane whereas the reduction in MCT1 expression was less in mitochondrial membrane. Training increased the MCT1 mRNA and protein expression in both membranes and decreased insulin resistance as an adaptive consequence. In both tissues increase in CD147 mRNA was only parallel to MCT1 expression. The response of MCT1 on sarcolemmal and mitochondrial membranes was different between cardiac and skeletal muscles which indicate that intracellular lactate kinetic is tissue specific that allows a tissue to coordinate whole organism metabolism.
我们假设耐力训练对胰岛素抵抗的部分治疗效果是通过增加心肌和骨骼肌线粒体乳酸转运蛋白、单羧酸转运蛋白 1（MCT1）介导的。因此，我们分别检查了 7 周的耐力训练对健康和 2 型糖尿病大鼠骨骼肌和线粒体膜上 MCT1 和 MCT4 及其伴侣蛋白 CD147 的 mRNA 和蛋白表达的影响。糖尿病是通过注射低剂量链脲佐菌素和高脂饮食喂养诱导的。胰岛素抵抗通过稳态模型评估估计的胰岛素抵抗指数来确认，并且通过阴性对照标志物（葡萄糖转运蛋白 1 和细胞色素 c 氧化酶）来确认两种膜分离的准确性。实时 PCR 和 Western blot 分别用于 mRNA 和蛋白表达的检测。糖尿病显著降低了 MCT1 和 MCT4 的 mRNA 及其在肌膜上的表达，而在线粒体膜上 MCT1 的表达减少较少。训练增加了两种膜上的 MCT1 mRNA 和蛋白表达，并作为适应性后果降低了胰岛素抵抗。在两种组织中，CD147 mRNA 的增加仅与 MCT1 表达平行。MCT1 在肌膜和线粒体膜上的反应在心脏和骨骼肌之间是不同的，这表明细胞内乳酸动力学是组织特异性的，允许组织协调整个生物体的代谢。
