Question

A child presented with dehydration and was supplemented with ORS solution for management. Which of the following receptors help in the absorption of glucose from GIT?

• A. SGLT 1
• B. SGLT 2
• C. GLUT 1
• D. GLUT 2

Hint:

Think about which sodium-glucose co-transporter sits on the luminal brush border of intestinal cells.

Answer 1

The Correct Option is A

Step 1: Understand glucose transporters in the GIT.
Glucose is transported across cell membranes by two main families: GLUT (facilitated diffusion) and SGLT (sodium-glucose co-transporters, active transport). While GLUT transporters predominate in most body tissues, the intestinal epithelium and renal tubules rely on SGLT transporters for luminal glucose uptake.

Step 2: Identify the relevant SGLT subtype.
SGLT 1 is expressed on the apical (luminal) brush border of small intestinal enterocytes. It co-transports 2 Na⁺ ions with each glucose molecule, using the inward sodium gradient to drive glucose absorption. SGLT 2 is expressed mainly in the proximal convoluted tubule of the kidney and handles about 90% of glucose reabsorption from the glomerular filtrate -- it is not the primary intestinal transporter.

Step 3: Apply to ORS context.
ORS contains both glucose and sodium. The sodium in ORS drives SGLT 1 on the luminal surface of the intestine, facilitating glucose and water co-absorption. This is the physiological basis of ORS therapy in dehydration.

Conclusion: SGLT 1 is the receptor responsible for glucose absorption from the GIT lumen.