骨骼肌不同类型肌纤维在收缩中两种形式糖原的分解状况

The Two Forms of Glycogenolysis in the Contracting of Different Types of Skeletal Muscles

测定与分析了不同类型肌纤维在收缩过程中两种形式糖原 (MG和 PG)的分解状况。雄性 Wister大鼠分为 2组 :低糖组 (L G)和高糖组 (HG) ,灌注自由下肢和同时电刺激 10 m in。收缩前后肌肉样本取自腓肠肌 (SOL) ,外侧胫骨白肌 (WG)和外侧胫骨红肌 (RG)用以分析 MG,PG和总糖原。结果表明 :在电刺激收缩过程中 ,MG和 PG同时作为底物被利用。在快收缩肌纤维 (WG和 RG)比慢收缩肌纤维 (Sol) MG和 PG分解明显增加。高糖组比低糖组 MG和 PG分解明显增加。不同类型肌纤维 MG百分含量与总糖原浓度呈高度正相关。提示 :肌纤维内

The two forms of glycogenolysis macroglycogen (MG) and proglycogen (PG) in different fibers during muscle contraction were determined and analyzed. Male Wistar rats were divided into two groups of low glycogen (LG) and high glycogen (HG). Isolated hindlimbs were perfused and electrically stimulated to contract for 10min. Pre and post contraction, muscle samples of soleus, white and red gastrocnemius were analyzed for MG, PG and total glycogen. The results show that both MG and PG were suitable substrates during the intensive contraction of rat skeletal muscle. The breakdown of MG and PG was markedly higher in fast switch fibers (WG and RG)than in slow switch fibers (Sol), and in HG group than in LG group. There existed close positive correlation between MG% and the total glycogen content in different types of muscle fibers. This may provide an explanation to the higher glycogenolytic rate found in glycogen supercompensated muscle.The results suggest that the mechanism underlying glycogen-dependent glycogenolytic rate is restricted to MG particles.