Atrial natriuretic factor

Atrial natriuretic factor (ANF), or atrial natriuretic peptide (ANP), is a peptide hormone that is released by walls of the cardiac atrium in response to high NaCl concentration, high extracellular fluid volume, or high blood volume. ANF inhibits NaCl reabsorption in the distal convoluted tubule and cortical collecting duct of kidney nephrons. It also dilates the afferent glomerular arteriole and constricts the efferent glomerular arteriole. This increases the glomerular filtration rate, which increases the amount of NaCl excretion and thereby increases the urinary filtration rate.