Hypophysial hormone that stimulates reabsorption of water and electrolyte by the distal tubules of kidneys is :

Options

A. Oxytocin
B. Aldosterone
C. Cortisol
D. Vasopressin

Answer

To solve the question regarding the hypophysial hormone that stimulates the reabsorption of water and electrolytes by the distal tubules of the kidneys, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Hormones**: The question provides four options: oxytocin, aldosterone, cortisol, and vasopressin. We need to analyze each hormone to determine which one is responsible for the reabsorption of water and electrolytes in the kidneys.

2. **Analyze Oxytocin**:
- Oxytocin is primarily involved in stimulating contractions of smooth muscles, particularly during childbirth and lactation.
- It does not play a significant role in kidney function or the reabsorption of water and electrolytes.
- **Conclusion**: Oxytocin is not the correct answer.

3. **Analyze Aldosterone**:
- Aldosterone is a steroid hormone produced by the adrenal cortex.
- It promotes the reabsorption of sodium ions in the kidneys, which indirectly leads to water retention, but it primarily acts on the distal tubules and collecting ducts.
- **Conclusion**: While aldosterone is involved in electrolyte balance, it is not classified as a hypophysial hormone (pituitary hormone).

4. **Analyze Cortisol**:
- Cortisol is another steroid hormone from the adrenal cortex, mainly involved in glucose metabolism and stress response.
- It does not directly stimulate the reabsorption of water and electrolytes in the kidneys.
- **Conclusion**: Cortisol is not the correct answer.

5. **Analyze Vasopressin (ADH)**:
- Vasopressin, also known as antidiuretic hormone (ADH), is released from the posterior pituitary gland (hypophysis).
- It specifically acts on the kidneys to promote the reabsorption of water and electrolytes, particularly in the distal tubules and collecting ducts.
- **Conclusion**: Vasopressin is the correct answer as it directly stimulates water reabsorption in the kidneys.

6. **Final Answer**: The hypophysial hormone that stimulates reabsorption of water and electrolytes by the distal tubules of the kidneys is **vasopressin**.