Intestinal epithelial cells possess 2 transport mechanisms to move glucose across the plasma membrane, a facilitated glucose carrier (GLUT2) as well as a sodium-dependent secondary active transporter (SGLT1). Which of the following attributes distinguishes these 2 transport modalities with respect to net glucose transport?

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Quizplus · Accepted Answer

SGLT1 is a Na⁺-dependent glucose cotransporter. Within the kidney tubule, the Na⁺ / K⁺ -ATPase pump on the basolateral membrane of the proximal tubule cell uses ATP to move Na+ outward into the blood, while bringing in 2 K⁺. This creates a downhill Na+ gradient inside the proximal tubule cell in comparison to both the blood and the tubule. SGLT1 uses the energy from this downhill Na+ gradient created by the ATPase pump to transport glucose across the apical membrane against an uphill glucose gradient

Intestinal Epithelial Cells Possess 2 Transport Mechanisms to Move Glucose