[Atrial Natriuretic Peptide and Its Significance for Arterial Hypertension]

Atrial natriuretic peptide is a recently discovered cardiac hormone with natriuretic, vasodilatory and hypotensive activities. The role of this hormone in the pathophysiology of hypertension is of particular interest. In contrast to an earlier concept, a deficiency of the atrial peptide could not be found in animal models of hypertension or in patients. ANP plasma levels were elevated in SHR with accelerated hypertension, in salt-sensitive Dahl rats, in rats with DOCA-salt-hypertension and in animals with renovascular hypertension. Elevated ANP levels under these conditions can be explained by an expansion of the intravascular volume or by an elevated atrial wall stretch induced by the hypertension itself. In patients with primary hypertension, plasma levels of the peptide are raised in some patients and are normal in others. Plasma ANP levels correlate with age, blood pressure and signs of left ventricular hypertrophy. A negative correlation is described between ANP and renin. Measurement of plasma ANP levels does not allow a differentiation between primary and secondary forms of hypertension. Elevated ANP levels are also found in primary hyperaldosteronism and in renal failure. Stimulation of ANP secretion by physical exercise and dietary salt loading is maintained in hypertension. Infusion of 1-28-hANP leads to a reduction in systemic arterial pressure in normotensives and hypertensives. The natriuresis induced by exogenous ANP is more pronounced in hypertensives. Stimulation of endogenous ANP secretion does not prevent the rise in blood pressure possibly due to a reduction in ANP receptors in target tissues.