Which of the following is an action of Angiotensin II?

• A. Sodium reabsorption in proximal tubule
• B. Sodium excretion in distal tubule
• C. Vasodilation of efferent arteriole
• D. Inhibition of ADH release

Answer: (A)

Angiotensin II promotes sodium reabsorption in the proximal tubule by activating the apical Na+/H+ exchanger (NHE3), which drives Na+ (and accompanying water) re back from the filtrate into the blood. This helps conserve volume and maintain blood pressure when kidney perfusion is reduced. The proximal tubule reabsorption is a primary way Ang II supports fluid balance, especially during RAAS activation.

That’s why this option fits Ang II’s action. It does not cause sodium excretion in the distal tubule, it constricts the efferent arteriole (not dilates it), and it stimulates, rather than inhibits, ADH release to promote water reabsorption.