- The hormone that primarily promotes sodium reabsorption in the distal convoluted tubule of the nephron is aldosterone.
- Aldosterone is a mineralocorticoid secreted by the adrenal cortex in response to signals such as low blood pressure, low sodium levels, or high potassium levels.
- It acts on the cells of the distal convoluted tubule and collecting duct to increase the expression and activity of sodium channels and sodium-potassium ATPase pumps.
- This results in enhanced sodium reabsorption back into the bloodstream, which helps to increase blood volume and blood pressure.

- While antidiuretic hormone (ADH) primarily regulates water reabsorption in the collecting ducts, it does not directly stimulate sodium reabsorption.
- Parathyroid hormone (PTH) mainly influences calcium and phosphate handling in the nephron, particularly in the proximal tubule and thick ascending limb, but not sodium.
- Atrial natriuretic peptide (ANP), on the other hand, has the opposite effect by promoting natriuresis, which is the excretion of sodium to reduce blood volume and pressure.

Therefore, the key hormone responsible for sodium reabsorption in the distal convoluted tubule is aldosterone.

Reference: Guyton and Hall Textbook of Medical Physiology, 13th Edition, Chapter 26: Renal Function