Carrier-mediated Transport Systems for Glucose in Mucosal Cells of the Human Oral Cavity

The in vitro uptake study was performed using the isolated cells of human oral mucosa, buccal and the dorsum of the tongue, to investigate the mechanisms of glucose uptake. The uptake of D-glucose was much larger in cells of the dorsum of the tongue than in buccal cells and was inhibited more extensively by 2-deoxy-D-glucose, a substrate of facilitative glucose transporters, than by alpha-methyl-D-glucoside, a specific substrate of SGLT1, suggesting the larger contribution of a facilitative transporter than Na(+)/glucose cotransporter. Furthermore, from the results of inhibition studies by several sugar analogues including maltose and D-mannose, GLUT1 and/or GLUT3 were suggested to take part in the glucose uptake by oral mucosa. Therefore, we have attempted to confirm the expression of glucose transporters on the oral mucosa by employing Western blotting. As a result, it was suggested that SGLT1, GLUT1, GLUT2, and GLUT3 are expressed in the epithelial cells of human oral mucosa.