Atrial Natriuretic Factor (ANF) is a peptide hormone secreted by the atrial walls of our heart in response to the increases blood pressure. This hormone reduces the reabsorption of Na⁺ ions from the glomerular filtrate into the blood, resulting into the excretion of Na⁺ ions along with large amount of water through the urine (natriuresis). It also dialates the blood vessels (acting as a vasodialator) thereby lowering the blood pressure and restoring back the normal body conditions.