Vasopressin, also known as antidiuretic hormone (ADH), is a hormone produced by the hypothalamus and released by the pituitary gland. It plays a crucial role in regulating the body's water balance by promoting water reabsorption in the kidneys. This helps to concentrate urine and maintain blood pressure. In addition to its role in water regulation, vasopressin also influences blood vessel constriction, which can increase blood pressure. It is involved in various bodily functions, including social behavior and stress response, making it an important hormone for overall health and homeostasis.