Question

Which of the following causes an increase in sodium reabsorption in the distal convoluted tubule?

• A. Increase in antidiuretic hormone levels
• B. Decrease in aldosterone levels
• C. Decrease in antidiuretic hormone levels
• D. Increase in aldosterone levels

Answer 1

The Correct Option is D

An increase in sodium reabsorption in the distal convoluted tubule is primarily influenced by the hormone aldosterone. Let's explore the options to understand why an increase in aldosterone levels is the correct answer:

1. Antidiuretic Hormone (ADH): ADH primarily affects water reabsorption in the kidney, particularly within the collecting ducts, by making them more permeable to water. An increase in ADH levels does not directly cause an increase in sodium reabsorption in the distal convoluted tubule. Therefore, this option is incorrect.
2. Aldosterone: Aldosterone is a steroid hormone produced by the adrenal cortex. It plays a crucial role in regulating sodium and potassium balance. Aldosterone acts on the distal convoluted tubule and the collecting duct to increase sodium reabsorption into the bloodstream and potassium excretion into the urine. When aldosterone levels increase, more sodium is reabsorbed. Therefore, this option is correct.
3. Decrease in ADH levels: This would lead to less water reabsorption, potentially increasing urine output, but it does not directly affect sodium reabsorption in the distal convoluted tubule. Therefore, this option is incorrect.
4. Decrease in Aldosterone levels: This would result in decreased sodium reabsorption, as aldosterone is not promoting sodium uptake. Therefore, this option is incorrect.

Given the functions of these hormones, the correct answer is indeed an increase in aldosterone levels, which enhances sodium reabsorption in the distal convoluted tubule.