PENTOSE CYCLE AND INSULIN RELEASE IN ISOLATED MOUSE PANCREATIC-ISLETS DURING STARVATION
PENTOSE CYCLE AND INSULIN RELEASE IN ISOLATED MOUSE PANCREATIC-ISLETS DURING STARVATION
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DOI：
10.1042/bj1520571
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发表时间：
1975-01-01
影响因子：
4.1
通讯作者：
CAPITO, K
中科院分区：
文献类型：
--
作者：
HEDESKOV, CJ;CAPITO, K
当小鼠的胰岛与 16.7 mM 葡萄糖一起孵育时，之前 48 小时的饥饿使胰岛素释放率降低了约 10%。 50%，葡萄糖利用率下降约 50%。 35%。饥饿后葡萄糖6-磷酸脱氢酶的最大可提取活性降低了28%。然而，在进食和饥饿小鼠的胰岛中，[1-14C]葡萄糖形成 14CO2 的速率高于[6-14C]-葡萄糖的氧化速率。所利用的被氧化的葡萄糖比例（比 14CO2 产量）为五分之一到三分之一，并且在以 [1-14C] 葡萄糖和 [6-14C] 葡萄糖作为底物的饥饿小鼠的胰岛中更高。戊糖循环氧化对总葡萄糖代谢的贡献很小（进食状态下为 3%，饥饿状态下为 4%）。通过戊糖循环氧化的葡萄糖碳代谢至总葡萄糖代谢的绝对速率很小（进食状态下为 3%，饥饿状态下为 4%）。在进食和饥饿动物的胰岛中，通过戊糖循环的葡萄糖碳代谢的绝对速率以及该途径中 NADPH 的周转率是相同的。在16.7 mM葡萄糖下孵育30分钟后，饥饿时葡萄糖（6-磷酸盐和6-磷酸葡萄糖酸盐）的含量均没有变化。得出的结论是，饥饿期间胰岛素分泌机制的敏感性降低与通过戊糖循环的葡萄糖代谢、胰岛葡萄糖6-磷酸盐或6-磷酸葡萄糖酸盐的含量之间不存在相关性。
When islets from mice were incubated with 16.7 mM-glucose, previous starvation for 48 h decreased the rate of insulin release by approx. 50% and glucose utilization was decreased by approx. 35%. The maximally extractable activity of glucose 6-phosphate dehydrogenase was diminished by 28% after starvation. The formation of 14CO2 from both [1-14C]glucose was, however, higher than the rate of oxidation of [6-14C]-glucose in islets from both fed and starved mice. The fraction of glucose utilized that was oxidized (specific 14CO2 yield) ranged from one-fifth to one-third and was higher in islets from starved mice with both [1-14C]glucose and [6-14C]glucose as substrate. The contribution of pentose-cycle oxidation to total glucose metabolism was small (3% in the fed state and 4% in the starved state). The absolute rates of glucose carbon metabolism via the pentose-cycle oxidation to total glucose metabolism was small (3% in the fed state and 4% in the starved state). The absolute rates of glucose carbon metabolism via the pentose cycle and the turnover of NADPH in this pathway were identical in islets from fed and starved animals. After incubation at 16.7 mM-glucose for 30 min the contents of glucose (6-phosphate and 6-phosphogluconate were both unchanged by starvation. It is concluded that there is no correlation between the decreased sensitivity of the insulin secretory mechanism during starvation and the metabolism of glucose via the pentose cycle, the islet content of glucose 6-phosphate or 6-phosphogluconate.