Atrial natriuretic peptides in man

Research on the physiological role of atrial peptides in man is limited, and the potential for these peptides, or more stable analogues, in therapeutics is uncertain. It is clear, however, that plasma levels of immunoreactive atrial natriuretic peptide (IR-ANP) are increased in volunteers taking a high sodium diet, and are elevated in patients with heart failure, chronic renal failure, and primary aldosteronism. There is suggestive evidence that IR-ANP levels are increased also in essential hypertension, although overlap with normotensives is considerable. Injection or infusion of atrial peptides into man results in a diuresis, an increased output of urine electrolytes, a fall in blood pressure and a rise in heart rate, suppression of aldosterone and sometimes of renin also, and stimulation of norepinephrine. In essential hypertensives, urinary effects may be greater than in normotensives. Heart failure patients show a rise in cardiac output and falls in both systemic and pulmonary arterial pressure. Over the next few years and especially if specific antagonists can be developed, the physiologic and pathophysiologic roles of atrial peptides in normal man and in clinical disorders should be clarified. It is possible that stable analogues of atrial peptides will find a place in the treatment of cardiac failure, renal failure, and perhaps hypertension.