The main function of polaction hormone is to :-

Options

A. Influence the of thyroid gland
B. Control development of graffian follicles
C. Initiate and maintain secretion of milk by mammary gland
D. Cause ejection

Answer

### Step-by-Step Solution:

1. **Identify the Hormone**: The question refers to the prolactation hormone, which is commonly known as prolactin.

2. **Source of Prolactin**: Prolactin is produced and released by the anterior pituitary gland in the brain.

3. **Main Function of Prolactin**: The primary role of prolactin is to regulate the growth and development of the mammary glands in females.

4. **Milk Production**: Prolactin is crucial for initiating and maintaining milk production in the mammary glands after childbirth. This process is essential for breastfeeding.

5. **Elimination of Incorrect Options**:
- **Influence the Thyroid Gland**: Prolactin does not primarily influence the thyroid gland; this function is associated with thyroid hormones like T3 and T4.
- **Control Development of Graafian Follicles**: The development of Graafian follicles is regulated by Follicle Stimulating Hormone (FSH), not prolactin.
- **Cause Ejection of Milk**: While prolactin is involved in milk production, the ejection of milk (let-down reflex) is primarily controlled by oxytocin.

6. **Correct Answer**: Therefore, the main function of prolactin is to initiate and maintain the secretion of milk by the mammary glands.

### Final Answer:
The main function of prolactin hormone is to initiate and maintain secretion of milk by the mammary glands.

---