desmopressin
A synthetic analogue of vasopressin in which 3-mercaptopropionic acid replaces the cysteine residue at position 1 and D-arginine replaces the residue at position 8. An antidiuretic, it increases urine concentration and decreases urine production, and is used (usually as the trihydrate of the acetic acid salt) to prevent and control excessive thirst, urination, and dehydration caused by injury, surgery, and certain medical conditions. It is also used in the diagnosis and treatment of cranial diabetes insipidus and in tests of renal function.
