Which one of the following is a peptide hormone ?

Options

A. Glucagon
B. Testosterone
C. Thyroxine
D. Adrenaline

Answer

### Step-by-Step Solution

1. **Understanding Hormones**: Hormones are classified based on their structure and origin. They can be categorized into three main types:
- Lipid-derived hormones
- Amino acid-derived hormones
- Peptide hormones

2. **Defining Peptide Hormones**: Peptide hormones are larger molecules made up of chains of amino acids. They typically consist of 2 or more amino acids linked together. Examples include insulin and glucagon.

3. **Analyzing the Given Options**: The question asks to identify which of the following is a peptide hormone. The options provided are:
- Glucagon
- Testosterone
- Thyroxine
- Adrenaline

4. **Identifying Each Hormone**:
- **Glucagon**: This is a peptide hormone composed of 29 amino acids and is produced by the pancreas.
- **Testosterone**: This is a lipid-derived hormone, specifically a steroid hormone.
- **Thyroxine**: This hormone is derived from the amino acid tyrosine and is produced by the thyroid gland, making it amino acid-derived.
- **Adrenaline**: Also derived from amino acids, specifically from tyrosine.

5. **Conclusion**: Among the given options, glucagon is the only peptide hormone.

### Final Answer
The peptide hormone among the options is **Glucagon**.

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