[Effects of water immersion and captopril on secretion of atrial natriuretic peptide and the activity of the renin-angiotensin system in essential hypertension].

In 31 patients with essential hypertension (EH) and in 21 healthy subjects, the influence of water immersion (WI) on arterial blood pressure, plasma renin activity, plasma aldosterone and atrial natriuretic peptide was examined after administration of captopril. In other 15 patients with EH and 25 healthy subjects, the influence of WI without captopril pretreatment on the above mentioned parameters was assessed. Plasma renin activity and plasma aldosterone concentration did not differ in patients with EH and in healthy subjects. In contrast, plasma atrial natriuretic peptide concentration was significantly higher but its response to WI-induced "central hypervolemia" significantly less marked in patients with EH than in healthy subjects. Results obtained in this study do not confirm presence of a tight interrelationship between atrial natriuretic peptide secretion and activity of the renin-angiotensin-aldosterone system both in patients with EH and in healthy subjects.