Which of the following hormones is the main mineralocorticoid ?

Options

A. Aldosterone
B. Cortisol
C. ADH
D. Adrenaline

Answer

To determine which hormone is the main mineralocorticoid, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Source of Corticoids**:
- Corticoids are hormones that are released from the adrenal cortex, which is the outer part of the adrenal glands located on top of the kidneys.

2. **Identify Types of Corticoids**:
- There are three main types of corticoids produced by the adrenal cortex:
- Mineralocorticoids
- Glucocorticoids
- Sex corticoids

3. **Focus on Mineralocorticoids**:
- Mineralocorticoids are primarily involved in the regulation of mineral balance in the body, particularly sodium (Na+) and potassium (K+) levels.

4. **Identify the Main Mineralocorticoid**:
- The primary mineralocorticoid hormone is **aldosterone**. Aldosterone plays a crucial role in the reabsorption of sodium and water in the kidneys, specifically in the distal convoluted tubule (DCT) of the nephron.

5. **Function of Aldosterone**:
- Aldosterone promotes the reabsorption of sodium (Na+) and the excretion of potassium (K+) in the kidneys. This action helps to maintain blood pressure and fluid balance in the body.

6. **Conclusion**:
- Therefore, the answer to the question is **aldosterone**, as it is the main mineralocorticoid hormone.

### Final Answer:
The main mineralocorticoid is **aldosterone**.