Talmadge R J, Silverman H
Department of Zoology and Physiology, Louisiana State University, Baton Rouge 70803.
Am J Physiol. 1993 Mar;264(3 Pt 1):E328-33. doi: 10.1152/ajpendo.1993.264.3.E328.
The hindlimb muscles of the C57Bl6J dy2J/dy2J (dy2J) mouse suffer from a chronic neural stimulation (pseudomyotonia), resulting in increased contractile activity. In response to the increased contractile activity, these muscles store increased amounts of glycogen. In this study, glucose uptake and glycogenesis (glycogen synthesis from glucose) were analyzed in chronically active and normal muscles. In vivo experiments demonstrate increased 3-O-methylglucose (3-MG) uptake rates and glycogenesis by chronically active dy2J gastrocnemius muscles (Gast) vs. normal control Gast. The chronically active diaphragm muscle (Dia) showed the highest rates of 3-MG uptake, as well as glycogenesis in vivo when compared with other skeletal muscles. No differences were observed between dy2J and control Dia. The levels of blood glucose were similar between dy2J and control animals. In vitro experiments demonstrated an increased sensitivity and responsiveness to insulin for glucose uptake in the dy2J soleus muscle (Sol). Glycogenesis by dy2J Sol was elevated only at the highest insulin concentration tested (10,000 microU/ml). In contrast, the dy2J extensor digitorum longus muscle had an increased sensitivity and responsiveness to insulin for both glucose uptake and glycogenesis. This study demonstrates that chronically active muscles have elevated capacities for glucose uptake and glycogenesis and may help to explain the elevated glycogen levels in the dy2J hindlimb muscles.
C57Bl6J dy2J/dy2J（dy2J）小鼠的后肢肌肉患有慢性神经刺激（假肌强直），导致收缩活动增加。作为对增加的收缩活动的反应，这些肌肉储存了更多的糖原。在本研究中，对长期活跃和正常的肌肉中的葡萄糖摄取和糖原生成（由葡萄糖合成糖原）进行了分析。体内实验表明，与正常对照的腓肠肌相比，长期活跃的dy2J腓肠肌（Gast）的3 - O - 甲基葡萄糖（3 - MG）摄取率和糖原生成增加。与其他骨骼肌相比，长期活跃的膈肌（Dia）在体内显示出最高的3 - MG摄取率以及糖原生成率。dy2J和对照的Dia之间未观察到差异。dy2J和对照动物之间的血糖水平相似。体外实验表明，dy2J比目鱼肌（Sol）对胰岛素介导的葡萄糖摄取具有更高的敏感性和反应性。dy2J Sol的糖原生成仅在测试的最高胰岛素浓度（10,000微单位/毫升）下升高。相比之下，dy2J趾长伸肌对胰岛素介导的葡萄糖摄取和糖原生成均具有更高的敏感性和反应性。本研究表明，长期活跃的肌肉具有更高的葡萄糖摄取和糖原生成能力，这可能有助于解释dy2J后肢肌肉中糖原水平的升高。
