Influence of Hypotensive Therapy on Plasma Endothelin Concentration in Patients with Essential Hypertension

Abstract

Background Endothelins (ET) are peptides of 21-amino acides which have variety of biological actions but the most important is vasoconstrictor action. There are many factors that may influence ET concentration and functional effect. Among those factors the most important role seem to have angiotensin-converting enzyme inhibitors (ACE-I) and calcium antagonists (CA).
Material and methods A group of 70 patients with essential hypertension and 10 healthy subjects were examined. 50 patients were treated with ACE -I(20 with captopril and 30 with trandolapril) and 20 with CA (nifedipine). We measured: blood pressure (BP), ET concentration, aldosterone (Ald) concentration and plasma renin activity (PRA).
Results suggest that: 1) single dose of captopril leads to significant decrease of BP and ET concentration, increase of PRA. 2) Short (7 days) therapy with trandolapril induces significant decrease of BP, ET. 3) 1 month therapy with trandolapril leads to significant decrease of BP, ET concentration and increase of PRA. 4) Single dose of nifedipine causes significant decrease of BP, while decrease of ET concentration is not significant. 5) In all groups non-significant decrease of serum Ald concentration was noticed. 6) In hypertensive patients in comparison with the control group (healthy subjects) we observed significantly higher BP and Ald concentration, while differences in ET concentration and PRA were non-significant. 7) There were no correlation between BP and ET values in hypertensive patients.
Conclusions 1) Beneficial effect of ACE inhibitors may be partly due to the marked lowering of endothelin concentration, a mitogenic substance and powerful vasoconstrictor. 2)Contrary to ACE inhbitors, calcium channel blockers do not influence endothelin concentraction in patiens with essential hypertension. 3)The average endothelin concentraction inpatients with essential hypertension was not significantly deferent from its cocentraction in control subjects.