Spironolactone primarily acts on which section of the nephron?

Spironolactone primarily acts on the collecting duct of the nephron, not the distal convoluted tubule. This medication is a potassium-sparing diuretic that antagonizes the action of aldosterone in the distal nephron, particularly in the collecting ducts. By blocking aldosterone's effects, spironolactone inhibits sodium reabsorption and promotes sodium and water excretion while retaining potassium.

In the context of the nephron, this action is crucial because the collecting duct is responsible for fine-tuning the body's electrolyte and fluid balance, and the influence of aldosterone is significant here. Aldosterone's role typically involves promoting sodium reabsorption in exchange for potassium excretion; by inhibiting this process, spironolactone can be effective in conditions where excess fluid retention is a concern.

Understanding the specific site of action for spironolactone is vital for comprehending its therapeutic uses and the physiological implications of its mechanism.