Which of these hormones decrease the amount of sodium lost by the body through urine ?

Options

A. ANF
B. Aldosterone
C. Parathormone
D. Vasopressin .

Answer

To solve the question "Which of these hormones decrease the amount of sodium lost by the body through urine?", we will analyze each of the given hormones and their functions related to sodium regulation.

### Step-by-Step Solution:

1. **Identify the Hormones**: The hormones listed are:
- Atrial Natriuretic Factor (ANF)
- Aldosterone
- Parathormone
- Vasopressin

2. **Understand the Function of ANF**:
- ANF is released by the right atrium of the heart.
- Its primary role is to promote natriuresis, which means it helps in the excretion of sodium through urine.
- Therefore, ANF **increases** sodium loss, not decreases it.

**Hint**: ANF promotes sodium excretion.

3. **Understand the Function of Aldosterone**:
- Aldosterone is secreted by the adrenal cortex and is classified as a mineralocorticoid.
- Its main function is to increase sodium reabsorption in the kidneys, specifically in the distal convoluted tubule (DCT).
- By increasing sodium reabsorption, aldosterone effectively **decreases** the amount of sodium lost in urine.

**Hint**: Aldosterone helps retain sodium in the body.

4. **Understand the Function of Parathormone**:
- Parathormone (or parathyroid hormone) is secreted by the parathyroid glands.
- Its primary role is in calcium metabolism, increasing calcium levels in the blood.
- It does not have a direct effect on sodium reabsorption or loss.

**Hint**: Parathormone is mainly involved in calcium regulation.

5. **Understand the Function of Vasopressin**:
- Vasopressin, also known as antidiuretic hormone (ADH), is secreted by the posterior pituitary gland.
- Its primary function is to increase water reabsorption in the kidneys, which helps to concentrate urine.
- While it affects water balance, it does not directly influence sodium reabsorption.

**Hint**: Vasopressin focuses on water retention, not sodium.

6. **Conclusion**:
- Based on the functions of the hormones analyzed, the hormone that decreases the amount of sodium lost by the body through urine is **Aldosterone**.

### Final Answer:
The correct answer is **Aldosterone**.