All of the following pairs of hormones are antagonistic, except

Options

A. Calcitonin and parathormone
B. Cortisol and insulin
C. Insulin and glucagon
D. Calcitriol and Collips hormone

Answer

To solve the question regarding which pair of hormones is not antagonistic, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Antagonistic Hormones**: Antagonistic hormones are those that have opposite effects on the same physiological function. For example, if one hormone increases a certain level in the body, the other hormone decreases it.

2. **Identify the Hormone Pairs**: The question provides several pairs of hormones. We need to analyze each pair to determine if they are antagonistic or not.

3. **Analyze Each Pair**:
- **Pair 1: Calcitonin and Parathormone**:
- Calcitonin decreases blood calcium levels.
- Parathormone increases blood calcium levels.
- **Conclusion**: This pair is antagonistic.

- **Pair 2: Cortisol and Insulin**:
- Cortisol increases blood glucose levels.
- Insulin decreases blood glucose levels.
- **Conclusion**: This pair is antagonistic.

- **Pair 3: Insulin and Glucagon**:
- Insulin decreases blood glucose levels.
- Glucagon increases blood glucose levels.
- **Conclusion**: This pair is antagonistic.

- **Pair 4: Calcitriol and Calbindin Hormone**:
- Calcitriol (active form of Vitamin D) promotes calcium absorption.
- Calbindin also promotes calcium absorption.
- **Conclusion**: This pair is not antagonistic; they are synergistic (they work together).

4. **Select the Correct Answer**: Since the question asks for the pair that is not antagonistic, the correct answer is **Calcitriol and Calbindin Hormone**.

### Final Answer:
The correct option is **D: Calcitriol and Calbindin Hormone**.

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