Select the option which correctly describes the function of given hormones.

Options

A. Parathormone : Decreases blood Calcium
B. Cortisol : Decreases blood glucose level
C. Vasopressin : stimulates reabsorption of `Na^+`
D. Androgen : Stimulates erythropoiesis

Answer

To solve the question regarding the correct functions of the given hormones, we will evaluate each hormone and its described function step by step.

### Step 1: Evaluate Parathyroid Hormone
- **Function Described**: Decreases calcium level in blood.
- **Actual Function**: Parathyroid hormone (PTH) is responsible for increasing the calcium levels in the blood by stimulating the release of calcium from bones, increasing calcium reabsorption in the kidneys, and promoting the activation of vitamin D to increase intestinal absorption of calcium.
- **Conclusion**: This statement is incorrect.

**Hint**: Remember that parathyroid hormone increases blood calcium levels, not decreases.

### Step 2: Evaluate Cortisol
- **Function Described**: Decreases blood glucose level.
- **Actual Function**: Cortisol is a glucocorticoid hormone that primarily increases blood glucose levels by promoting gluconeogenesis in the liver and inhibiting glucose uptake in other tissues. It also plays a role in the body’s stress response.
- **Conclusion**: This statement is incorrect.

**Hint**: Cortisol is known as the stress hormone and is associated with increasing blood glucose levels.

### Step 3: Evaluate Vasopressin
- **Function Described**: Stimulates reabsorption of sodium ions.
- **Actual Function**: Vasopressin, also known as antidiuretic hormone (ADH), primarily regulates water retention in the body by increasing water reabsorption in the kidneys. It does not primarily stimulate sodium reabsorption.
- **Conclusion**: This statement is incorrect.

**Hint**: Vasopressin is mainly involved in water retention, not sodium reabsorption.

### Step 4: Evaluate Androgen
- **Function Described**: Stimulates erythropoiesis.
- **Actual Function**: Androgens, such as testosterone, can stimulate erythropoiesis (the production of red blood cells) by promoting the production of erythropoietin (EPO) and influencing the bone marrow.
- **Conclusion**: This statement is correct.

**Hint**: Androgens are linked to the stimulation of red blood cell production.

### Final Conclusion
After evaluating all the options, the only correct description of the hormone function is for androgens, which stimulate erythropoiesis. Therefore, the correct answer is **Option 4**.