Final answer:
Atrial natriuretic factor (ANF) inhibits sodium reabsorption, leading to the excretion of sodium in the urine.
Step-by-step explanation:
The atrial natriuretic factor (ANF) inhibits sodium reabsorption. ANF, also known as atrial natriuretic peptide (ANP), is released by cells in the atrium of the heart in response to high blood pressure. It acts on the renal tubules to prevent the reabsorption of sodium, leading to the excretion of sodium in the urine. This mechanism helps to decrease blood volume and lower blood pressure.