Regulation of glycogen utilization, but not glucose utilization, by precontraction glycogen levels in vascular smooth muscle.
Regulation of glycogen utilization, but not glucose utilization, by precontraction glycogen levels in vascular smooth muscle.
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通过血管平滑肌中预收缩糖原水平调节糖原利用，但不调节葡萄糖利用。
DOI：
10.1021/bi970465a
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Roberts,TM
中科院分区：
文献类型：
--
作者：
Hardin,CD;Roberts,TM
这些实验旨在确定糖原分解是否受到血管平滑肌糖原浓度的影响。猪颈动脉平滑肌片段被允许合成不同量的1-[13C]葡萄糖基单位的糖原。然后动脉段在2-[13C]葡萄糖存在下等长收缩。在等长收缩之前和之后，测量组织糖原含量以及过流葡萄糖和乳酸浓度。使用 13 C-NMR光谱测量过融合物中的2-[ 13 C]乳酸盐和3-[ 13 C]乳酸盐峰强度。尽管收缩前糖原浓度范围超过 3 倍，但在 4.5 小时等长收缩期间，组织糖原含量呈指数下降（R2= 0.990）。 3小时等长收缩期间糖原利用程度与收缩前糖原浓度呈线性变化（R2 = 0.727）。特别是来自糖原分解的乳酸产量随着收缩前糖原浓度的增加而增加（R2 = 0.620）。在 3 小时等长收缩期间，葡萄糖利用率（R2 = 0.007）和由葡萄糖特异产生的乳酸产量（R2 = 0.000 02）均不随收缩前糖原浓度变化。结论是，糖原分解的速率是由长时间收缩期间糖原的含量决定的。此外，收缩前糖原水平影响糖原利用途径，但不影响葡萄糖利用途径。因此，糖酵解和糖原分解在血管平滑肌中独立发挥作用。
These experiments were designed to determine whether glycogenolysis was influenced by the glycogen concentration of vascular smooth muscle. Segments of hog carotid artery smooth muscle were allowed to synthesize variable amounts of 1-[13C]glucosyl units of glycogen. Artery segments were then isometrically contracted in the presence of 2-[13C]glucose. Prior to and after isometric contraction, measurements were made of tissue glycogen content and superfusate glucose and lactate concentrations. 2-[13C]Lactate and 3-[13C]lactate peak intensities in the superfusate were measured using13C-NMR spectroscopy. The tissue glycogen content decreased exponentially during the 4.5 h of isometric contraction (R2= 0.990), despite more than a 3-fold range of glycogen concentration prior to contraction. The extent of glycogen utilization during a 3 h isometric contraction varied linearly with the precontraction glycogen concentration (R2= 0.727). Lactate production specifically from glycogen breakdown increased with an increase in precontraction glycogen concentration (R2= 0.620). During a 3 h isometric contraction neither the glucose utilization (R2= 0.007) nor lactate production specifically produced from glucose (R2= 0.000 02) varied with the precontraction glycogen concentration. It is concluded that the rate of glycogenolysis is determined by the content of glycogen during prolonged contractions. In addition, precontraction glycogen levels influence the pathway for glycogen utilization but not the pathway for glucose utilization. Therefore, glycolysis and glycogenolysis behave independently in vascular smooth muscle.