The reabsorption of the sodium from glomerular filtrate is regulated by the hormone

Options

A. glucagon
B. secretin
C. aldosterone
D. adrenaline.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which hormone regulates the reabsorption of sodium from the glomerular filtrate in the kidneys.

2. **Identifying the Hormones**: The options provided are glucagon, secretin, aldosterone, and adrenaline. We need to analyze each hormone to determine which one is responsible for sodium reabsorption.

3. **Analyzing Glucagon**:
- Glucagon is secreted by the alpha cells of the islets of Langerhans in the pancreas.
- Its primary function is to convert glycogen into glucose, increasing blood glucose levels.
- **Conclusion**: Glucagon does not regulate sodium reabsorption.

4. **Analyzing Secretin**:
- Secretin is a gastrointestinal hormone that regulates gastric acid secretion and pancreatic bicarbonate production.
- It is involved in osmoregulation but does not play a role in sodium reabsorption.
- **Conclusion**: Secretin does not regulate sodium reabsorption.

5. **Analyzing Aldosterone**:
- Aldosterone is secreted by the adrenal cortex.
- Its main function is to increase sodium ion reabsorption in the distal convoluted tubule (DCT) of the nephron, often in exchange for potassium ions.
- This process also promotes water reabsorption, which helps regulate blood pressure and fluid balance.
- **Conclusion**: Aldosterone is responsible for regulating sodium reabsorption.

6. **Analyzing Adrenaline**:
- Adrenaline (or epinephrine) is secreted by the adrenal medulla.
- It primarily functions as a stress hormone, increasing heart rate and blood pressure during emergencies.
- **Conclusion**: Adrenaline does not regulate sodium reabsorption.

7. **Final Answer**: Based on the analysis, the hormone that regulates the reabsorption of sodium from glomerular filtrate is **aldosterone**. Therefore, the correct answer is the third option.

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