Which of the following hormones contains iodine ?

Options

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

Explanation

To determine which of the following hormones contains iodine, we will analyze each option provided.

### Step-by-Step Solution:

1. **Identify the Hormones**: We need to look at the list of hormones given in the options. The common hormones we will consider are Insulin, Testosterone, Adrenaline, and Thyroxine.

2. **Analyze Insulin**:
- Insulin is a peptide hormone produced by the pancreas.
- It is made up of amino acids, which do not contain iodine.
- **Conclusion**: Insulin does not contain iodine.

3. **Analyze Testosterone**:
- Testosterone is a male sex hormone produced in the testes.
- It is a steroid hormone and does not contain iodine in its structure.
- **Conclusion**: Testosterone does not contain iodine.

4. **Analyze Adrenaline**:
- Adrenaline (also known as epinephrine) is produced by the adrenal glands.
- It acts as a neurotransmitter and is also a catecholamine, which does not include iodine in its structure.
- **Conclusion**: Adrenaline does not contain iodine.

5. **Analyze Thyroxine**:
- Thyroxine (T4) is a hormone produced by the thyroid gland.
- It is known to contain iodine in its structure, specifically it has four iodine atoms.
- **Conclusion**: Thyroxine contains iodine.

6. **Final Answer**:
- After analyzing all the options, the hormone that contains iodine is **Thyroxine**.