LACK OF EVIDENCE FOR THE INTERACTION BETWEEN RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM AND ENDOTHELIN IN-VIVO

Aim of the study was to reveal the possible factors regulating plasma endothelin (ET) levels in vivo in patients with essential hypertension (EH) by the simultaneous determination of plasma renin activity (PRA) and plasma aldosterone (ALD). In addition, the possible relationship between ET and circulating endothelial cells as a marker of endothelia l damage was also investigated. The postural test revealed a significa nt increase of ET levels (26.7+/-9 vs 11.5+/-3 fmol/ml, p<0.05) in the upright position. Captopril administration did not change plasma ET l evels. No significant correlation was found between ET and PRA or ALD. Although a tendency to a positive correlation between ET and circulat ing endothelial cells (as the marker of endothelial perturbation) was found, it did not attain statistical significance. Our data do not sup port the suggestion that the renin-angiotensin-aldosterone system play s a major role in the regulation of ET secretion in vivo in EH. Postur al stimulation of ET secretion may be caused by other factors than ren in-angiotensin-aldosterone system.