Which hormone is mainly secreted by corpus luteum ?

Options

A. Luteinizing hormone
B. Estrogen
C. Follicle stimulating hormone
D. Progesterone

Explanation

**Step-by-Step Solution:**

1. **Identify the Structure**: The corpus luteum is a temporary endocrine structure involved in the menstrual cycle and early pregnancy.

2. **Understand the Function**: The primary function of the corpus luteum is to secrete hormones that are crucial for maintaining the uterine lining and supporting early pregnancy.

3. **List the Hormones**: The corpus luteum primarily secretes two hormones: estrogen and progesterone.

4. **Determine the Main Hormone**: Among the hormones secreted by the corpus luteum, progesterone is the primary hormone that plays a vital role in preparing the uterus for implantation of a fertilized egg and maintaining pregnancy.

5. **Eliminate Other Options**:
- Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are produced by the anterior pituitary gland, not the corpus luteum.
- While estrogen is produced by the corpus luteum, it is not the main hormone; progesterone is considered the primary hormone.

6. **Conclusion**: Therefore, the hormone mainly secreted by the corpus luteum is progesterone.

**Final Answer**: D. Progesterone

---