Islet-cell metabolism during insulin release. Effects of glucose, citrate, octanoate, tolbutamide, glucagon and theophylline.
Islet-cell metabolism during insulin release. Effects of glucose, citrate, octanoate, tolbutamide, glucagon and theophylline.
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胰岛素释放过程中的胰岛细胞代谢。
DOI：
10.1042/bj1150257
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发表时间：
1969
期刊：
影响因子：
--
通讯作者：
K. Taylor
中科院分区：
文献类型：
--
作者：
BY W. Montague;K. Taylor
1. 研究了从大鼠胰腺分离的朗格汉斯胰岛中葡萄糖6-磷酸和6-磷酸葡萄糖酸盐的浓度，并在各种诱导胰岛素释放的药物的存在下孵育。2. 随着细胞外葡萄糖浓度的升高（2-10mm），细胞内葡萄糖6-磷酸浓度呈线性增加，但6-磷酸葡萄糖酸盐的情况并非如此，只有当外部葡萄糖浓度超过5mm时，细胞内葡萄糖6-磷酸浓度才会增加。甲磺丁胺、辛酸盐和柠檬酸盐均可促进离体胰岛的胰岛素分泌，增加细胞内葡萄糖6-磷酸和6-磷酸葡萄糖酸盐的浓度。在辛酸盐和柠檬酸盐存在下获得的结果与柠檬酸盐对胰岛细胞磷酸果糖激酶的抑制作用是相容的。4. 茶碱和胰高血糖素与胰岛体外培养时促进胰岛素释放，引起6-磷酸葡萄糖酸盐浓度升高，而不是6-磷酸葡萄糖浓度升高。5. 这表明，通过糖酵解以外的途径进一步代谢葡萄糖6-磷酸对胰岛素释放至关重要。其中一种途径涉及其氧化为6-磷酸葡萄糖酸盐，这似乎是葡萄糖分泌胰岛素的必要伴随物。讨论了除葡萄糖外的其他药物通过增强葡萄糖6-磷酸的氧化来促进胰岛素释放的可能性。
1. Concentrations of glucose 6-phosphate and 6-phosphogluconate were studied in islets of Langerhans isolated from rat pancreas and incubated in the presence of various agents that induce insulin release. 2. In response to rising concentrations of extracellular glucose (2-10mm) there is a linear increase in the intracellular concentration of glucose 6-phosphate, though this is not the case for 6-phosphogluconate, the intracellular concentration of which only increases when the external glucose concentration exceeds 5mm. 3. Tolbutamide, octanoate and citrate, all of which promote insulin secretion from isolated islets, increase the intracellular concentrations of glucose 6-phosphate and 6-phosphogluconate. The results obtained in the presence of octanoate and citrate are compatible with an inhibitory effect of citrate on islet-cell phosphofructokinase. 4. Theophylline and glucagon when incubated with islets in vitro promote insulin release and cause a rise in 6-phosphogluconate concentration and not in that of glucose 6-phosphate. 5. It is suggested that the further metabolism of glucose 6-phosphate through a pathway other than glycolysis is essential for insulin release. One such pathway involves its oxidation to 6-phosphogluconate, which seems to be a necessary accompaniment of insulin secretion due to glucose. The possibility that agents other than glucose promote insulin release by enhancing the oxidation of glucose 6-phosphate through this pathway is discussed.