In which part of the kidney does Angiotensin II cause Na+ reabsorption?

Angiotensin II primarily acts on the proximal convoluted tubule and the adrenal cortex to regulate sodium reabsorption in the kidneys. While the distal convoluted tubule is involved in sodium handling, the most significant action of Angiotensin II occurs at the collecting duct through the stimulation of aldosterone secretion, which enhances sodium reabsorption in that segment.

In the collecting duct, Angiotensin II initiates a series of processes that ultimately lead to increased sodium reabsorption. The hormone promotes the activity of sodium channels and sodium-potassium pumps on the principal cells of the collecting duct. This not only increases sodium retention but also contributes to the regulation of blood volume and blood pressure.

The combined effects of these actions illustrate how Angiotensin II is crucial for maintaining electrolyte balance and fluid homeostasis within the body, particularly through its influence on sodium reabsorption in the collecting duct.