Liver glucose metabolism in humans.
Liver glucose metabolism in humans.
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DOI：
10.1042/bsr20160385
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发表时间：
2016-12
影响因子：
4
通讯作者：
Pazos-García C
中科院分区：
文献类型：
--
作者：
Adeva-Andany MM;Pérez-Felpete N;Fernández-Fernández C;Donapetry-García C;Pazos-García C
关于正常肝脏糖代谢的信息可能有助于了解肥胖和糖尿病的致病机制。此外，肝脏葡萄糖代谢参与糖基化反应，并与脂肪酸代谢有关。肝脏通过门静脉直接从肠道接受膳食碳水化合物。葡萄糖激酶在肝细胞内将葡萄糖磷酸化为葡萄糖6-磷酸，确保足够的葡萄糖流进入细胞进行代谢。葡萄糖- 6-磷酸可经过几种代谢途径。在餐后期间，大多数葡萄糖6-磷酸被用来合成糖原，通过形成葡萄糖1-磷酸和udp -葡萄糖。少量的udp -葡萄糖被用来形成udp -葡萄糖酸盐和udp -半乳糖，它们是糖基化中使用的单糖单位的供体。葡萄糖6-磷酸代谢的第二个途径是果糖6-磷酸的形成，它可以通过己糖胺途径生成udp - n -乙酰氨基葡萄糖，也可以通过糖酵解途径生成丙酮酸，然后生成乙酰辅酶A。当肝细胞内存在过量葡萄糖时，乙酰辅酶a可能进入三羧酸（TCA）循环被氧化或输出到细胞质合成脂肪酸。最后，葡萄糖6-磷酸可能通过戊糖磷酸途径产生NADPH和核糖5-磷酸。葡萄糖代谢为糖基化提供中间体，糖基化是蛋白质和脂质的翻译后修饰，可调节其活性。先天性缺乏磷酸葡萄糖糖化酶(PGM)-1和PGM-3与糖基化受损有关。除了代谢碳水化合物外，肝脏还通过糖原分解或主要通过乳酸和丙氨酸重新合成（糖异生）产生供其他组织使用的葡萄糖。
Information about normal hepatic glucose metabolism may help to understand pathogenic mechanisms underlying obesity and diabetes mellitus. In addition, liver glucose metabolism is involved in glycosylation reactions and connected with fatty acid metabolism. The liver receives dietary carbohydrates directly from the intestine via the portal vein. Glucokinase phosphorylates glucose to glucose 6-phosphate inside the hepatocyte, ensuring that an adequate flow of glucose enters the cell to be metabolized. Glucose 6-phosphate may proceed to several metabolic pathways. During the post-prandial period, most glucose 6-phosphate is used to synthesize glycogen via the formation of glucose 1-phosphate and UDP–glucose. Minor amounts of UDP–glucose are used to form UDP–glucuronate and UDP–galactose, which are donors of monosaccharide units used in glycosylation. A second pathway of glucose 6-phosphate metabolism is the formation of fructose 6-phosphate, which may either start the hexosamine pathway to produce UDP-N-acetylglucosamine or follow the glycolytic pathway to generate pyruvate and then acetyl-CoA. Acetyl-CoA may enter the tricarboxylic acid (TCA) cycle to be oxidized or may be exported to the cytosol to synthesize fatty acids, when excess glucose is present within the hepatocyte. Finally, glucose 6-phosphate may produce NADPH and ribose 5-phosphate through the pentose phosphate pathway. Glucose metabolism supplies intermediates for glycosylation, a post-translational modification of proteins and lipids that modulates their activity. Congenital deficiency of phosphoglucomutase (PGM)-1 and PGM-3 is associated with impaired glycosylation. In addition to metabolize carbohydrates, the liver produces glucose to be used by other tissues, from glycogen breakdown or from de novo synthesis using primarily lactate and alanine (gluconeogenesis).