3. Atrial Natriuretic Factor (ANF)

ANF is a group of vasoactive peptides released when the atria are distended and low pressure stretch receptors in the atrial walls are stimulated. ANF causes a sodium diuresis (natriuresis or excretion of a sodium rich urine) and contributes to a vasodilatation of constricted vessels.

Atrial distension will occur as a result of increased blood pressure and this mechanism is part of the homeostatic response.