Vasopressins

**Definition:** Antidiuretic hormones released by the NEUROHYPOPHYSIS of all vertebrates (structure varies with species) to regulate water balance and OSMOLARITY. In general, vasopressin is a nonapeptide consisting of a six-amino-acid ring with a cysteine 1 to cysteine 6 disulfide bridge or an octapeptide containing a CYSTINE. All mammals have arginine vasopressin except the pig with a lysine at position 8. Vasopressin, a vasoconstrictor, acts on the KIDNEY COLLECTING DUCTS to increase water reabsorption, increase blood volume and blood pressure.

**Tree numbers:** - D06.472.699.631.692.781 - D12.644.400.900 - D12.644.456.925 - D12.644.548.691.692.781 - D12.776.631.650.937

**Synonyms:** - beta-Hypophamine - Antidiuretic Hormones - Antidiuretic Hormone