Thiazide diuretics primarily act on which part of the nephron?

Thiazide diuretics primarily act on the distal convoluted tubule (DCT) of the nephron. The mechanism of action involves inhibiting the sodium-chloride symporter located in the luminal membrane of the DCT cells, leading to decreased reabsorption of sodium and chloride. This inhibition results in increased excretion of these electrolytes, alongside water, which causes diuresis.

The distal convoluted tubule is crucial because it fine-tunes the electrolyte balance in the body, and thiazide diuretics effectively enhance water and electrolyte loss, making them beneficial for conditions like hypertension and edema.

In contrast, the proximal convoluted tubule and both loops of Henle handle sodium and water reabsorption differently and do not respond to thiazide diuretics. For example, the proximal convoluted tubule primarily reabsorbs bicarbonate, glucose, and amino acids, while the loops of Henle are involved in creating a concentration gradient for urine formation and are primarily targeted by loop diuretics, not thiazides.