ANF acts as a check on renin-angiotensin mechanism.

Atrial natriuretic peptide (ANF) acts as a counter-regulatory hormone to the renin-angiotensin-aldosterone system. While the renin-angiotensin system works to increase blood pressure and fluid retention, ANF opposes these effects. ANF is released by the atria of the heart in response to increased blood volume and stretching of the atrial walls. It promotes vasodilation, increases excretion of sodium and water by the kidneys, and inhibits the release of renin. This counter-regulatory action helps maintain a balance in fluid and electrolyte homeostasis.