ldentify the hormone which performs the following functions -
I. Maintenance of water and electrolyte balance
II. Regulation of BMR
III. Regulation of erythropoiesis

Options

A. Thyroxine
B. Adrenaline
C. ACTH
D. Estrogen

Answer

To solve the question of identifying the hormone that performs the functions of maintenance of water and electrolyte balance, regulation of BMR (Basal Metabolic Rate), and regulation of erythropoiesis, we can analyze each option provided.

### Step-by-Step Solution:

1. **Understanding the Functions**:
- **Maintenance of Water and Electrolyte Balance**: This function is crucial for homeostasis and involves hormones that regulate fluid balance in the body.
- **Regulation of BMR**: The Basal Metabolic Rate is the rate at which the body uses energy while at rest, and it is primarily regulated by thyroid hormones.
- **Regulation of Erythropoiesis**: This refers to the production of red blood cells, which can be influenced by certain hormones.

2. **Analyzing the Options**:
- **Thyroxine**: This hormone is secreted by the thyroid gland and is known to regulate BMR. It also plays a role in maintaining water and electrolyte balance and has been shown to promote erythropoiesis.
- **Adrenaline**: This hormone is secreted by the adrenal medulla and is primarily involved in the 'fight or flight' response. It does not regulate BMR or erythropoiesis.
- **ACTH (Adrenocorticotropic Hormone)**: This hormone is secreted by the pituitary gland and stimulates the adrenal cortex to release cortisol. It does not directly regulate BMR or erythropoiesis.
- **Estrogen**: This hormone is primarily involved in the female reproductive system and does not perform the functions listed in the question.

3. **Conclusion**:
- Based on the analysis, **Thyroxine** is the hormone that performs all three functions mentioned in the question: maintenance of water and electrolyte balance, regulation of BMR, and regulation of erythropoiesis.

### Final Answer:
The hormone that performs the functions of maintenance of water and electrolyte balance, regulation of BMR, and regulation of erythropoiesis is **Thyroxine**.

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