Scruel O, Sener A, Malaisse W J
Laboratory of Experimental Medicine, Brussels Free University, Belgium.
Mol Cell Biochem. 1999 Jul;197(1-2):209-16. doi: 10.1023/a:1006910201767.
In the light of recent findings on the effect of D-glucose upon D-fructose phosphorylation by human B-cell glucokinase, the influence of the aldohexose upon the metabolism of the ketohexose was investigated in rat pancreatic islets. D-glucose, although slightly decreasing D-[5-(3)H]fructose utilization, augmented the oxidation of the ketohexose, indicating that the aldohexose stimulates preferentially the oxidative, as distinct from anaerobic, modality of glycolysis. Such was not the case in parotid cells, taken as representative of functionally nonglucose-responsive cells. In the islets exposed to D-fructose, D-glucose also decreased the fractional contribution of the pentose shunt to the generation of CO2 and D-glyceraldehyde 3-phosphate from the ketohexose, and increased the inflow into the Krebs cycle of dicarboxylic metabolites relative to that of fructose-derived acetyl-CoA. This glucose-induced remodeling of D-fructose metabolism may optimize the insulin secretory response of islet cells to these hexoses, e.g. after food intake.
鉴于最近关于D-葡萄糖对人B细胞葡萄糖激酶催化D-果糖磷酸化作用的研究结果，我们在大鼠胰岛中研究了己醛糖对己酮糖代谢的影响。D-葡萄糖虽然略微降低了D-[5-(3)H]果糖的利用，但增加了己酮糖的氧化，这表明己醛糖优先刺激糖酵解的氧化方式，而非无氧方式。在作为功能上对葡萄糖无反应细胞代表的腮腺细胞中则并非如此。在暴露于D-果糖的胰岛中，D-葡萄糖还降低了戊糖旁路对己酮糖生成CO2和D-甘油醛3-磷酸的贡献率，并相对于果糖衍生的乙酰辅酶A增加了二羧酸代谢物进入三羧酸循环的流量。这种葡萄糖诱导的D-果糖代谢重塑可能会优化胰岛细胞对这些己糖的胰岛素分泌反应，例如在进食后。
