GLUT2在小肠糖吸收中的作用  

THE ROLE OF GLUT2 IN INTESTINAL GLUCOSE ABSORPTION

作　　者：魏娜[1,2] 刘瑞[1] 

机构地区：[1]四川大学华西医院生物治疗国家重点实验室人类疾病相关多肽研究室,成都610041 [2]华西医院消化内科

出　　处：《现代预防医学》2010年第23期4425-4427,4430,共4页Modern Preventive Medicine

基　　金：国家自然科学基金项目(30870919)

摘　　要：近年来的研究发现小肠葡萄糖的吸收包括两大部分,当小肠肠腔葡萄糖浓度低于血糖浓度时,由钠-葡萄糖协同转运蛋白1(SGLT1)介导的经典的主动吸收途径完成转运,当肠腔葡萄糖浓度高于SGLT1的糖转运饱和度时,葡萄糖转运蛋白2(GLUT2)在小肠一过性插入顶膜导致的易化扩散中起到了主导作用。由于具有低亲和力,高容量的特点,GLUT2确保了细胞内外葡萄糖的双向扩散。此外,GLUT2还参与了果糖和半乳糖的转运。生理状态下,小肠GLUT2主要存在于基底膜,饮食、激素、能量代谢等因素的影响可使其一过性易位至顶膜参与糖转运。病理状态下顶膜GLUT2永久性的插入,引起糖吸收增加,最终导致肥胖、胰岛素抵抗及糖尿病。It has been recently reported that there are two mechanisms of intestinal glucose absorption.When luminal glucose is lower than blood glucose,the absorption occurs via sodium-dependent glucose transporter 1（SGLT1）through the classical active transport.Once the glucose concentration in the intestine is beyond the transport saturation of SGLT1,the diffusion is dominately mediated by the transient insertion of glucose transporter type 2（GLUT2）into the apical membrane.Because of its low affinity and high capacity,GLUT2 enables the extra-and intracellular diffusion of glucose bidirectionally.In addition,GLUT2 is also involved in the transport of frucose and galactose.Under physiological conditions,GLUT2 is mainly located in the basolateral membrane of intestine,and could be transiently inserted into the apical membrane by the regulation of diets,hormones and energy metabolism to participate in the sugar metabolism.However,permanent apical GLUT2 in insertion pathological state may result in increased sugar absorption and lead to obesity,insulin-resistance and diabetes at last.

关 键 词：GLUT2 易化扩散 小肠 糖吸收 SGLT1 

分 类 号：R34[医药卫生—基础医学]