Synonyms: ADH, antidiuretic hormone
Related tests: renin, ACTH, Na, K
Clinical significanceClinical indicationsSample typePreparation
Clinical significance
Vasopressin is a hormone produced in the hypothalamus and then carried along nerve axons to the posterior pituitary, where it is stored until it is secreted into the blood when needed. Vasopressin acts on the distal convoluted tubules of the kidney, stimulating water reabsorption. A lack of vasopressin, or the inability of the nephron to respond to it, underlies diabetes insipidus.
Clinical indications
Suspected diabetes insipidus.
Sample type
The patient must have a blood sample taken.
Preparation
You must fast for at least 8 hours; a small amount of water is allowed. You must have been standing or sitting upright for at least 30 minutes.