Which of the following is not involved in the endocrine secretion ?

Options

A. Leydig cell
B. Lutein cell
C. Para - follicular cells of thyroid
D. Kupffer cells

Answer

To solve the question "Which of the following is not involved in the endocrine secretion?", we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understand Endocrine Secretion**:
- Endocrine secretion refers to the release of hormones directly into the bloodstream by glands or cells that are part of the endocrine system.

2. **Evaluate the Options**:
- **Option 1: Lutein Cells**:
- Lutein cells are involved in the production of hormones such as progesterone and estrogen. Therefore, they are part of the endocrine system.
- **Option 2: Theca Lutein Cells**:
- Theca lutein cells produce androgens and progesterone, which are hormones involved in the reproductive system. Hence, they are also part of the endocrine system.
- **Option 3: Parafollicular Cells of Thyroid**:
- Parafollicular cells (also known as C cells) secrete calcitonin, a hormone that helps regulate calcium levels in the blood. Thus, they are involved in endocrine secretion.
- **Option 4: Kupffer Cells of the Liver**:
- Kupffer cells are specialized macrophages located in the liver. They are not involved in hormone secretion but rather play a role in the immune response and the breakdown of pathogens. Therefore, they are not part of the endocrine system.

3. **Conclusion**:
- After analyzing all the options, we find that **Option 4: Kupffer Cells of the Liver** is the correct answer as they are not involved in endocrine secretion.

### Final Answer:
**Option 4: Kupffer Cells of the Liver**