Which of the following is/are correct statement(s) about the non-iodised hormone secreted by thyroid gland ?

Options

A. It is secreted by parafollicular cells
B. It is secreted in response to hypercalcemia
C. It is antagonistic to PTH
D. All of these

Answer

To answer the question regarding the correct statements about the non-iodized hormone secreted by the thyroid gland, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Identify the Non-Iodized Hormone**:
- The non-iodized hormone secreted by the thyroid gland is known as thyrocalcitonin (TCT), commonly referred to as calcitonin.

2. **Evaluate Statement 1**:
- Statement: "It is secreted by para follicular cells."
- Analysis: This statement is correct. Calcitonin is indeed secreted by parafollicular cells (also known as C cells) located in the thyroid gland.

3. **Evaluate Statement 2**:
- Statement: "It is secreted in response to hypercalcemia."
- Analysis: This statement is also correct. Calcitonin is released when there are high levels of calcium in the blood (hypercalcemia) to help lower those levels.

4. **Evaluate Statement 3**:
- Statement: "It is antagonistic to PTH."
- Analysis: This statement is correct as well. Calcitonin works in opposition to parathyroid hormone (PTH), which increases blood calcium levels. Calcitonin helps to lower blood calcium levels.

5. **Conclusion**:
- Since all the statements are correct, the final answer is that all of the statements about the non-iodized hormone (calcitonin) secreted by the thyroid gland are true. Therefore, the correct option is "all of these".

### Final Answer:
The correct answer is option 4: All of these statements are correct regarding the non-iodized hormone secreted by the thyroid gland.

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