Question

Glucose is transported in renal tubular cells by?

• A. K symport
• B. K antiport
• C. Na antiport
• D. Na cotransport

Hint:

SGLT1 and SGLT2 move Na and glucose in the same direction = cotransport.

Answer 1

The Correct Option is D

Step 1: Glucose is reabsorbed across the apical (luminal) membrane of the proximal renal tubular cells by sodium-dependent glucose transporters, SGLT1 and SGLT2.

Step 2: In these carriers glucose and Na+ bind together and move in the same direction into the cell. This is secondary active transport: glucose is dragged in against its gradient as Na+ flows down its electrochemical gradient. Movement of two solutes in the same direction is termed symport or cotransport.

Step 3: The low intracellular Na+ that powers this is maintained by the basolateral Na+/K+ ATPase. Antiport (a, c) means opposite directions, which does not describe Na-glucose handling, and there is no K-glucose symport (a, b) in the tubule.

Step 4: Hence glucose is transported by Na cotransport (Na-glucose symport), option (d).