What is the primary action of diuretics in the kidney?

What is the primary action of diuretics in the kidney?

• A. Decrease renal absorption of Na+, leading to fluid loss and a decrease in blood volume.
• B. Increase renal absorption of Na+
• C. Directly inhibit aldosterone
• D. Block the Na+/K+ pump in the proximal tubule

Answer: (A)

Diuretics work by promoting loss of salt and water in the urine. The key idea is that they reduce the kidney’s reabsorption of sodium, which pulls water into the urine. This natriuresis (and accompanying diuresis) lowers extracellular fluid and blood volume, which is why diuretics help relieve edema and lower blood pressure. Different diuretics hit different parts of the nephron, but the unifying effect is less sodium reabsorption, not increased reabsorption. Some agents do affect aldosterone signaling or target specific transporters, but those are not the universal primary action of all diuretics.

Diuretics work by promoting loss of salt and water in the urine. The key idea is that they reduce the kidney’s reabsorption of sodium, which pulls water into the urine. This natriuresis (and accompanying diuresis) lowers extracellular fluid and blood volume, which is why diuretics help relieve edema and lower blood pressure. Different diuretics hit different parts of the nephron, but the unifying effect is less sodium reabsorption, not increased reabsorption. Some agents do affect aldosterone signaling or target specific transporters, but those are not the universal primary action of all diuretics.