Vasopressin, also known as antidiuretic hormone (ADH), is a hormone secreted by the posterior pituitary gland. The hormone plays an important role in regulating water balance in the body and constricting blood vessels. Some synonyms for vasopressin include: 1. ADH: short for antidiuretic hormone, the medical name for vasopressin. 2. Arginine vasopressin: another name for the hormone, derived from the amino acid it contains. 3. Pitressin: a brand name for the synthetic form of vasopressin used in medical treatments. 4. Posterior pituitary hormone: describes the anatomical origin of vasopressin. 5. Vasotocin: a similar hormone found in non-mammalian species.