Henriksen E J, Kirby C R, Tischler M E
Department of Biochemistry, University of Arizona, Tucson 85724.
J Appl Physiol (1985). 1989 Jun;66(6):2782-7. doi: 10.1152/jappl.1989.66.6.2782.
The time course of glycogen changes in soleus muscle recovering from 3 days of nonweight bearing by hindlimb suspension was investigated. Within 15 min and up to 2 h, muscle glycogen decreased. Coincidentally, muscle glucose 6-phosphate and the fractional activity of glycogen phosphorylase, measured at the fresh muscle concentrations of AMP, increased. Increased fractional activity of glycogen synthase during this time was likely the result of greater glucose 6-phosphate and decreased glycogen. From 2 to 4 h, when the synthase activity remained elevated and the phosphorylase activity declined, glycogen levels increased (glycogen supercompensation). A further increase of glycogen up to 24 h did not correlate with the enzyme activities. Between 24 and 72 h, glycogen decreased to control values, possibly initiated by high phosphorylase activity at 24 h. At 12 and 24 h, the inverse relationship between glycogen concentration and the synthase activity ratio was lost, indicating that reloading transiently uncoupled glycogen control of this enzyme. These data suggest that the activities of glycogen synthase and phosphorylase, when measured at physiological effector levels, likely provide the closest approximation to the actual enzyme activities in vivo. Measurements made in this way effectively explained the majority of the changes in the soleus glycogen content during recovery from nonweight bearing.
研究了比目鱼肌在经历3天的后肢悬吊非负重状态后恢复过程中糖原变化的时间进程。在15分钟内直至2小时，肌肉糖原减少。与此同时，在新鲜肌肉中AMP浓度下测得的肌肉6-磷酸葡萄糖和糖原磷酸化酶的分数活性增加。在此期间糖原合酶分数活性增加可能是6-磷酸葡萄糖增加和糖原减少的结果。在2至4小时，当合酶活性保持升高而磷酸化酶活性下降时，糖原水平增加（糖原超补偿）。糖原进一步增加直至24小时与酶活性无关。在24至72小时之间，糖原降至对照值，这可能是由24小时时高磷酸化酶活性引发的。在12和24小时，糖原浓度与合酶活性比之间的反比关系消失，表明重新加载暂时使该酶的糖原控制解偶联。这些数据表明，在生理效应物水平下测量的糖原合酶和磷酸化酶活性可能最接近体内实际酶活性。以这种方式进行的测量有效地解释了比目鱼肌糖原含量在从非负重状态恢复过程中的大部分变化。
