Question

Which of the following hormones plays a key role in kidney osmoregulation by promoting water reabsorption in the collecting ducts?

• A. Insulin.
• B. Glucagon.
• C. Antidiuretic hormone (ADH).
• D. Aldosterone.

Hint:

ADH regulates water balance in the body by increasing water reabsorption in the collecting ducts, especially during dehydration or high blood osmolarity.

Answer 1

The Correct Option is C

Step 1: Role of ADH in osmoregulation.
Antidiuretic hormone (ADH), also known as vasopressin, is released by the posterior pituitary gland. It increases water reabsorption in the collecting ducts of the nephron by increasing the permeability of the duct walls to water. Step 2: Explanation of other hormones.
Insulin (Option A): Incorrect. Insulin regulates glucose metabolism, not osmoregulation. Glucagon (Option B): Incorrect. Glucagon increases blood glucose levels and has no role in water reabsorption. Aldosterone (Option D): Incorrect. Aldosterone regulates sodium and potassium balance, indirectly affecting water reabsorption, but it is not the primary hormone for osmoregulation. \[ \therefore \text{The key hormone for water reabsorption in the collecting ducts is: Antidiuretic hormone (ADH).} \]