Topics:
Animal Physiology, Animal Refresher
Site of Glucose and Amino Acid Reabsorption in Kidney
Reabsorption of glucose and amino acids in the kidney occurs at:
- PCT by cotransport with Na⁺ — Correct Answer
- DCT by ion channel
- PCT by GLUT-2 protein
- PCT by passive diffusion
Explanation:
Correct Answer: PCT by cotransport with Na⁺
Glucose and amino acids are reabsorbed in the Proximal Convoluted Tubule (PCT) via secondary active transport — specifically by cotransport with Na⁺ (Na⁺-dependent cotransporters).
Mechanism of Glucose Reabsorption
- Luminal (apical) membrane: SGLT (Sodium-Glucose co-Transporter) — Na⁺ and glucose enter the cell together; driven by low intracellular Na⁺ maintained by Na⁺-K⁺-ATPase on basolateral side
- Basolateral membrane: GLUT-2 facilitates glucose exit from cell into peritubular capillaries by facilitated diffusion
Mechanism of Amino Acid Reabsorption
Similar to glucose — co-transported with Na⁺ at the luminal membrane via specific amino acid cotransporters. Different transporters exist for different amino acid groups (acidic, basic, neutral).
Why Other Options Are Wrong
- DCT by ion channel: DCT mainly handles Na⁺ reabsorption (via Na⁺-Cl⁻ cotransporter) and K⁺ secretion under aldosterone — glucose is NOT reabsorbed here
- PCT by GLUT-2: GLUT-2 is on the basolateral side (exit from cell), not the luminal (entry from tubular fluid) side
- PCT by passive diffusion: Glucose reabsorption is secondary ACTIVE transport, not passive diffusion
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
