Vasopressin stimulates constriction of the blood vessels. but vasopressin is also called

Options

A. Synovial fluid
B. Neurotransmitter
C. Antidiuretic hormone
D. Growth regulating substance

Answer

### Step-by-Step Solution:

1. **Understanding Vasopressin**: Vasopressin is a hormone that plays a crucial role in regulating blood pressure and fluid balance in the body. It is known for its ability to cause vasoconstriction, which is the narrowing of blood vessels.

2. **Function of Vasopressin**: When blood pressure decreases, vasopressin is released to constrict blood vessels, thereby increasing blood pressure. This hormone also promotes the reabsorption of water and sodium in the kidneys, which helps to conserve water and reduce urine output.

3. **Alternate Name for Vasopressin**: Due to its function in reducing urine output by promoting water reabsorption, vasopressin is also known as the **Antidiuretic Hormone (ADH)**. The term "antidiuretic" refers to its ability to prevent diuresis (the increased production of urine).

4. **Source of Vasopressin**: Vasopressin is secreted from the posterior pituitary gland, also known as the neurohypophysis. Its release is regulated by the hypothalamus, which monitors blood pressure and osmolarity.

5. **Conclusion**: Therefore, the answer to the question is that vasopressin is also called **Antidiuretic Hormone (ADH)**.