Definition

A hormone that helps blood vessels constrict and helps the kidneys control the amount of water and salt in the body. This helps control blood pressure and the amount of urine that is made. Vasopressin is made by a part of the brain called the hypothalamus and is secreted into the blood by the pituitary gland. Certain types of tumors may release high amounts of vasopressin, which can cause low levels of sodium in the blood and the body to retain water. Also called antidiuretic hormone and arginine vasopressin.