Which section of the nephron is influenced by spironolactone?

Spironolactone is a potassium-sparing diuretic that primarily acts on the cortical collecting tubule of the nephron. This site is located in the kidney's nephron and is responsible for the regulation of sodium and potassium balance. Spironolactone works as an antagonist to the mineralocorticoid receptor, which is activated by aldosterone, a hormone that promotes sodium reabsorption and potassium excretion.

By blocking the action of aldosterone in the cortical collecting tubule, spironolactone inhibits the reabsorption of sodium, resulting in increased sodium excretion and decreased potassium excretion. This unique mechanism allows for the retention of potassium, hence the term 'potassium-sparing'. The influence of spironolactone on this segment of the nephron is particularly important in the management of conditions like hypertension and heart failure, where reducing fluid overload is beneficial, while simultaneously preventing hypokalemia.

In contrast, the other sections of the nephron mentioned, such as the ascending loop of Henle, distal convoluted tubule, and proximal convoluted tubule, are influenced by different classes of diuretics. The ascending loop primarily responds to loop diuretics, the distal convoluted tubule interacts