Which statement best describes aldosterone's effect on sodium and potassium?

Which statement best describes aldosterone's effect on sodium and potassium?

• A. Increases reabsorption of Sodium and Calcium
• B. Increases reabsorption of Sodium and excretion of Potassium
• C. Increases excretion of Sodium and Reabsorption of Potassium
• D. Increases excretion of both Sodium and Potassium

Answer: (B)

Aldosterone’s main action in the kidney is to increase sodium reabsorption in the distal tubule and collecting ducts while promoting potassium excretion. It binds to mineralocorticoid receptors in principal cells, upregulating epithelial sodium channels (ENaC) on the apical membrane and Na+/K+-ATPase pumps on the basolateral side. This brings more Na+ back into the bloodstream, and to maintain charge balance, K+ is secreted into the tubule and excreted in urine. Water follows the reabsorbed sodium, increasing fluid volume. Calcium reabsorption is not a primary target of aldosterone, as calcium regulation is mainly controlled by parathyroid hormone and vitamin D. So the statement describing increased sodium reabsorption and potassium excretion is the best description.

Aldosterone’s main action in the kidney is to increase sodium reabsorption in the distal tubule and collecting ducts while promoting potassium excretion. It binds to mineralocorticoid receptors in principal cells, upregulating epithelial sodium channels (ENaC) on the apical membrane and Na+/K+-ATPase pumps on the basolateral side. This brings more Na+ back into the bloodstream, and to maintain charge balance, K+ is secreted into the tubule and excreted in urine. Water follows the reabsorbed sodium, increasing fluid volume. Calcium reabsorption is not a primary target of aldosterone, as calcium regulation is mainly controlled by parathyroid hormone and vitamin D.

So the statement describing increased sodium reabsorption and potassium excretion is the best description.