Which of the following hormones is responsible for regulating the reabsorption of water ?

Options

A. Adrenalin
B. Thyroxine
C. Vasopressin
D. Testosterone

Answer

To determine which hormone is responsible for regulating the reabsorption of water, we can analyze the given options step by step:

1. **Identify the hormones listed in the options**: The question mentions several hormones: Adrenaline, Thyroxine, Vasopressin, and Testosterone.

2. **Examine the function of each hormone**:
- **Adrenaline**: This hormone is produced by the adrenal glands and is primarily involved in the 'fight or flight' response, increasing heart rate and blood flow, but it does not regulate water reabsorption.
- **Thyroxine**: Released by the thyroid gland, thyroxine mainly regulates metabolism and energy levels in the body. It does not play a direct role in water reabsorption.
- **Vasopressin**: Also known as Antidiuretic Hormone (ADH), this hormone is secreted by the posterior pituitary gland and is specifically responsible for increasing water reabsorption in the kidneys, thus helping to regulate the body's water balance.
- **Testosterone**: This hormone is primarily involved in the development of male reproductive tissues and the regulation of bone mass and fat distribution. It does not have a role in water reabsorption.

3. **Conclusion**: Based on the functions of the hormones analyzed, the hormone responsible for regulating the reabsorption of water is **Vasopressin**.

Therefore, the correct answer is **Vasopressin** (option 3).