Aldosterone's primary renal effect is to increase what?

Aldosterone's primary renal effect is to increase what?

• A. Increases salt absorption and water absorption
• B. Increases salt excretion
• C. Decreases salt absorption
• D. Decreases water absorption

Answer: (A)

Aldosterone’s renal action centers on sodium and water handling. It acts on the cells of the distal nephron and collecting duct to boost sodium reabsorption by increasing the activity of epithelial sodium channels on the apical membrane and Na+/K+ ATPase on the basolateral side. As sodium is reabsorbed, water follows osmotically, so aldosterone raises both salt and water reabsorption, leading to reduced urine output and increased blood volume. It also promotes potassium secretion, but its primary renal effect relevant here is the increase in salt reabsorption and the consequent water reabsorption. It does not increase salt excretion or decrease water absorption.

Aldosterone’s renal action centers on sodium and water handling. It acts on the cells of the distal nephron and collecting duct to boost sodium reabsorption by increasing the activity of epithelial sodium channels on the apical membrane and Na+/K+ ATPase on the basolateral side. As sodium is reabsorbed, water follows osmotically, so aldosterone raises both salt and water reabsorption, leading to reduced urine output and increased blood volume. It also promotes potassium secretion, but its primary renal effect relevant here is the increase in salt reabsorption and the consequent water reabsorption. It does not increase salt excretion or decrease water absorption.