Topics:
Animal Physiology, Animal Refresher
Hormone for Water Reabsorption in DCT and Collecting Duct
The hormone responsible for reabsorption of water through DCT and collecting duct is:
- ADH — Correct Answer
- Cortisol
- Aldosterone
- Oxytocin
Explanation:
Correct Answer: ADH (Antidiuretic Hormone)
ADH (Antidiuretic Hormone / Vasopressin) is the hormone that controls water reabsorption at the Distal Convoluted Tubule (DCT) and Collecting Duct of the nephron.
Mechanism of Action
- ADH is produced in the hypothalamus and stored/released from the posterior pituitary.
- It acts on V2 receptors of DCT and collecting duct cells, increasing the insertion of aquaporin-2 (AQP2) water channels into the luminal membrane.
- This makes the tubule permeable to water, allowing water to be reabsorbed back into the blood (following osmotic gradient created by the medullary interstitium).
- Result: concentrated urine with less volume is excreted.
Clinical Example
- Diabetes Insipidus: ADH deficiency (Central DI) or receptor insensitivity (Nephrogenic DI) → water cannot be reabsorbed → polyuria (large volumes of dilute urine) and polydipsia (excessive thirst).
Major Stimulus for ADH Release
- Hyperosmolarity of blood (detected by osmoreceptors in hypothalamus)
- Hypovolemia (reduced blood volume)
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
