How does vasopressin work in the body?
Vasopressin (also called antidiuretic hormone, ADH) mainly acts by binding to specific vasopressin receptors on target tissues, changing how cells respond and triggering downstream signaling that alters water balance and vascular tone.
What does it do to the kidneys (ADH/antidiuretic effect)?
On kidney collecting-duct cells, vasopressin causes the kidney to reabsorb more water from the urine back into the bloodstream. Mechanistically, it does this through receptor signaling that increases water channel activity on the collecting-duct surface, which lowers urine volume and makes urine more concentrated.
What does it do to blood vessels (vasoconstriction)?
Vasopressin can also raise blood pressure by constricting blood vessels. It does this by acting on vascular smooth muscle cells through receptor-mediated signaling pathways that increase smooth muscle contraction, leading to vasoconstriction.
Which receptors does vasopressin bind to?
Vasopressin’s effects come from several receptor subtypes on different tissues, and those receptors determine whether the dominant outcome is water reabsorption, vasoconstriction, or both. The same hormone can therefore produce different effects depending on which receptors are present in a given tissue.
What determines whether vasopressin causes mainly antidiuresis or mainly vasoconstriction?
The balance depends on:
- The receptor subtype distribution in the kidney vs. blood vessels
- Dose and local exposure (higher systemic exposure tends to increase vascular effects)
- The physiologic state (for example, dehydration or shock changes how the body responds)
What clinical uses tie directly to its mechanism?
Because vasopressin increases renal water reabsorption and can constrict blood vessels, it is used in settings where clinicians want those effects, such as conditions involving impaired water regulation (antidiuretic role) or inadequate vascular tone (vasoconstrictor role).