Which one of the following hormone can change the chromosomal functions by binding with their receptors ?
1. Cortisol 2. Iodothyronine
3. Testosterone 4. Estradiol

Options

A. Only 3 & 4
B. Only 1, 2 and 3
C. All 1, 2, 3 & 4
D. Only 1 & 2

Answer

To determine which hormone can change chromosomal functions by binding with their receptors, we need to analyze each of the given options: cortisol, iodothyronine, testosterone, and estradiol.

### Step-by-Step Solution:

1. **Understanding Hormone Types**:
- Hormones can be classified into two main categories: steroid hormones and peptide hormones. Steroid hormones are lipid-soluble and can easily cross the cell membrane to bind to intracellular receptors.

2. **Analyzing Each Hormone**:
- **Cortisol**: This is a steroid hormone produced by the adrenal glands. It can pass through the cell membrane and bind to intracellular receptors, influencing gene expression and chromosomal functions.
- **Iodothyronine**: This is a thyroid hormone (like thyroxine) that also has intracellular receptors. It plays a role in regulating metabolism but is not primarily known for changing chromosomal functions.
- **Testosterone**: This is another steroid hormone that can pass through the cell membrane and bind to intracellular receptors. It is involved in male sexual development and can influence gene expression.
- **Estradiol**: This is a form of estrogen, a steroid hormone that can also cross cell membranes and bind to intracellular receptors. It plays a significant role in female reproductive functions and can influence gene expression.

3. **Identifying the Correct Answer**:
- All four hormones (cortisol, iodothyronine, testosterone, and estradiol) can bind to intracellular receptors. However, the question specifically asks for the hormone that can change chromosomal functions.
- Among these, **testosterone** is particularly recognized for its role in altering chromosomal functions related to male characteristics and reproductive functions.

4. **Conclusion**:
- Therefore, the hormone that can change chromosomal functions by binding with their receptors is **Testosterone** (Option 3).

### Final Answer:
**3. Testosterone**