Atrial natriuretic factor: physiologic actions and implications in congestive heart failure

Atrial natriuretic factor (ANF) represents a newly recognized hormone of cardiac origin. This peptide is synthesized by the myocardial cells of both atria and released by atrial stretch. The hormone promotes sodium and water excretion by the kidney, inhibits the renin-angiotensin-aldosterone system, and reduces systemic arterial pressure. Specific receptors for ANF are present in the kidney, adrenal glands, vascular smooth muscle, platelets and central nervous system. Congestive heart failure is characterized by increased circulating levels of ANF; however, there appears to be an attenuation in the renal response to the hormone. Recent investigations have reported the effect of systemic administration of synthetic ANF to normal individuals and those with congestive heart failure. The hormone may promote a significant natriuresis and diuresis in addition to reducing arterial pressure and inhibiting renin and aldosterone secretion. Substantial questions remain as to the full physiologic significance and therapeutic potential of this hormone.