Which hormone stimulates sodium reabsorption in exchange for potassium secretion?

The correct answer is Aldosterone because this hormone plays a crucial role in regulating electrolyte balance, particularly sodium and potassium levels in the body. Aldosterone, produced by the adrenal cortex, promotes the reabsorption of sodium ions from the renal tubules back into the bloodstream. In this process, potassium ions are secreted from the blood into the urine, leading to a decrease in potassium levels in the body.

This mechanism is vital for maintaining blood pressure and fluid balance, as sodium reabsorption helps increase water retention, which in turn can influence blood volume and pressure. By promoting sodium reabsorption and facilitating potassium excretion, Aldosterone helps ensure homeostasis within the body’s fluid and electrolyte balance.

The other options focus on different functions: ADH primarily regulates water balance by promoting water reabsorption, ANP is involved in the regulation of blood pressure and volume by promoting sodium excretion, and Natriuretic peptide generally acts to reduce blood volume and blood pressure by inhibiting sodium reabsorption. Therefore, Aldosterone specifically functions to stimulate sodium reabsorption in exchange for potassium secretion, making it the appropriate choice.