Effect of diet on glucose transporter site density along the intestinal crypt-villus axis

• Published in: The American journal of physiology Vol. 262; no. 6 Pt 1; p. G1060
• Main Authors: Ferraris, R P, Villenas, S A, Hirayama, B A, Diamond, J
• Format: Journal Article
• Language: English
• Published: United States 01.06.1992
• Subjects: Analysis of Variance; Animals; Autoradiography; Cells, Cultured; Dietary Carbohydrates - pharmacology; Jejunum - cytology; Jejunum - drug effects; Jejunum - metabolism; Kinetics; Male; Mice; Microvilli - drug effects; Microvilli - metabolism; Monosaccharide Transport Proteins - metabolism; Phlorhizin - metabolism; Reference Values; Regression Analysis; Tritium
• ISSN: 0002-9513
• DOI: 10.1152/ajpgi.1992.262.6.g1060

High-carbohydrate diets stimulate intestinal brush-border glucose uptake and increase the number of glucose-protectable phlorizin binding sites, but it has been unknown where along the crypt-villus axis these effects are expressed. We attacked this problem by three methods. First, by measuring phlorizin binding to isolated mouse enterocytes fractionated along the crypt-villus axis by the Weiser method, we identified a high-affinity binding site predominating from villus tip to midvillus and a site of possibly lower affinity predominating in the crypts. A high-carbohydrate diet increased by severalfold the density of the villus sites and probably also of the crypt sites, without changing their binding constants. Second, autoradiography revealed increased glucose-protectable phlorizin binding along the whole crypt-villus axis on a high-carbohydrate diet. Finally, a polyclonal antibody against the Na(+)-glucose cotransporter recognized a protein in the brush-border membrane of villus cells. Hence, substrate-dependent upregulation of intestinal glucose transport involves increased numbers of transporters along the crypt-villus axis.