Sodium-dependent glucose transporter

GGM. Several missense mutations in human sodium-dependent glucose transporters (SGLT1) have been described that cause GGM. 

Kobayashi, Y., Suzuki, M., Satsu, H., Arai, S., Hara, Y., Suzuki, K., Miyamoto, Y., and Shimizu, M., Green tea polyphenols inhibit the sodium-dependent glucose transporter of intestinal epithelial cells by a competitive mechanism, J. Agric. Food Chem., 48, 5618, 2000. 

Walgren, R.A., Lin, J.T., Kinne, R.K., and Walle, T., Cellular uptake of dietary flavonoid quercetin 4 -(3-glucoside by sodium-dependent glucose transporter SGLTl, J. Pharmacol Exp. Ther., 294, 837, 2000. 

Day, A.J. et al.. Absorption of quercetin-3-glucoside and quercetin-4 -glucoside in the rat small intestine the role of lactase phlorizin hydrolase and the sodium-dependent glucose transporter, Biochem. Pharmacol., 65, 1199, 2003. 

Figure 1. Models for the orientation of A.) Members of the facilitative glucose transporter family (CLUT1 to GLUT7), and B.) the sodium-dependent glucose transporter (SGLT1). The branched structure is at the site of glycosylation for both transporters. In A, the open residues represent amino acids which are identical in GLUT1 through GLUT5.

Malathi, P. Takahashi, M. (1990). Isolation and reconstitution of the sodium-dependent glucose transporter. Meth. Enzymol. 192,438-447. 

Figure 10.2 Illustration of the various forms of transporters and carriers working in an intestinal epithelial cell. Clue, glucose Nuc, nucleotide DP, dipeptides and ABC, ATP-binding cassette family transporter SLC5A1, sodium-dependent glucose transporter ...

SGLTl A sodium-dependent glucose transporter located on the luminal side of the intestinal epithelial cells. It will transport glucose and galactose across the intestinal cell using a sodium ion gradient. 

SGLT2 A sodium-dependent glucose transporter that has a high specificity for glucose and is specific to the kidney. 

Figure 4 Enlargement of intestinal brush border, showing that polyphenol glycosides are not absorbed, transported into the enterocyte by a transporter, or hydrolyzed by a brush-border enzyme. Dotted arrows represent pathways followed by the polyphenols. PP-Glyc are polyphenol glycosides, PP-Conj are polyphenol conjugates, SGLTl is the sodium-dependent glucose transporter, and LPH is lactase phlorizin hydrolase.

To measure the level of d-[6- H] glucose intake in Caco-2 cells, tritium-labeled glucose and immature LJE were added to a culture medium. Phloridzin is an inhibitor of sodium-dependent glucose transporters. Glucose intake was significantly suppressed in phloridzin-treated Caco-2 cells, but not in those treated with immature LJE (Fig. 15.7). 

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