Sugar Absorption in the Intestine: The Role of GLUT2

  • George L. Kellett
    Department of Biology (Area 3), The University of York, York YO10 5YW, United Kingdom;,
  • Edith Brot-Laroche
    Center Recherche des Cordeliers UMRS 872, 15 Rue de l'Ecole de Medecine, 75 006 Paris, France;,
  • Oliver J. Mace
    Department of Biology (Area 3), The University of York, York YO10 5YW, United Kingdom;,
  • Armelle Leturque
    Center Recherche des Cordeliers UMRS 872, 15 Rue de l'Ecole de Medecine, 75 006 Paris, France;,

抄録

<jats:p> Intestinal glucose absorption comprises two components. One is classical active absorption mediated by the Na<jats:sup>+</jats:sup>/glucose cotransporter. The other is a diffusive component, formerly attributed to paracellular flow. Recent evidence, however, indicates that the diffusive component is mediated by the transient insertion of glucose transporter type 2 (GLUT2) into the apical membrane. This apical GLUT2 pathway of intestinal sugar absorption is present in species from insect to human, providing a major route at high sugar concentrations. The pathway is regulated by rapid trafficking of GLUT2 to the apical membrane induced by glucose during assimilation of a meal. Apical GLUT2 is therefore a target for multiple short-term and long-term nutrient-sensing mechanisms. These include regulation by a newly recognized pathway of calcium absorption through the nonclassical neuroendocrine l-type channel Ca<jats:sub>v</jats:sub>1.3 operating during digestion, activation of intestinal sweet taste receptors by natural sugars and artificial sweeteners, paracrine and endocrine hormones, especially insulin and GLP-2, and stress. Permanent apical GLUT2, resulting in increased sugar absorption, is a characteristic of experimental diabetes and of insulin-resistant states induced by fructose and fat. The nutritional consequences of apical and basolateral GLUT2 regulation are discussed in the context of Western diet, processed foods containing artificial sweeteners, obesity, and diabetes. </jats:p>

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