SGLT-2 mediates glucose reabsorption in the kidney. SGLT-2 catalyzes the active transport of glucose (against a concentration gradient) across the luminal membrane by coupling it with the downhill transport of Na+. The inward Na+ gradient across the luminal epithelium is maintained by active extrusion of Na+ across the basolateral surface into the intracellular fluid. Glucose diffuses out of the cell down a concentration gradient via the basolateral facilitative transporter GLUT2.²⁰  Adapted from Ref. 20.