Which hormone increases sodium reabsorption in the distal convoluted tubule?

The hormone responsible for increasing sodium reabsorption in the distal convoluted tubule is aldosterone. Aldosterone is a corticosteroid hormone produced by the adrenal cortex, and it plays a critical role in regulating sodium and potassium balance in the body.

When aldosterone is secreted, it acts on the cells of the distal convoluted tubule and the collecting ducts in the kidneys. It promotes the expression and activity of sodium channels and sodium-potassium pumps, facilitating the reabsorption of sodium from the renal tubular fluid back into the blood. This action not only helps to maintain blood pressure but also affects water retention since sodium reabsorption influences water movement across cell membranes.

In contrast, insulin primarily regulates glucose metabolism and has minimal direct effects on sodium reabsorption. Cortisol, while having some influence on mineralocorticoid receptors, is more involved in metabolic regulation rather than direct sodium reabsorption. Antidiuretic hormone mainly focuses on water reabsorption in the kidneys rather than sodium, affecting the permeability of the collecting ducts to water rather than influencing sodium levels directly. Hence, aldosterone is specifically the hormone that increases sodium reabsorption in the distal convoluted tubule.