Background Contemporary treatment of hypertension comprises also drugs affecting endothelium, increasing synthesis of vasorelaxating agents and decreasing synthesis of vasoconstrictory substances. One of these substances is endothelin-1 (ET-1). Literature shows us variability of calcium antagonists (A-Ca²⁺) influence on ET-1 concentration. Synthesis of ET-1 depends on many physical and chemical factors which may be influenced by A-Ca²⁺ administration. Particularly important are adrenergic system and RAA system. The aim of this study was to assess the influence of amlodipine on plasma ET-1 and aldosterone concentrations in patients with essential hypertension.
Material and methods Investigation involved 11 patients with essential hypertension (SBP — Me 152,5 ± 6,8 mm Hg, DBP — Me 95,0 ± 3,44 mm Hg) without any additional diseases that might have influenced plasma ET-1 concentration.
In each patient were assessed: a) SBP and DBP; b) plasma ET-1 concentration (radioimmunoassay); c) plasma aldosterone concentration (radioimmunoassay); before (I measurement) and after 30 days (II measurement) of amlodipine administration (5 mg/d).
Results One-month therapy of 5 mg of amlodipine/day causes: 1. significant decrease of SBP (Me ± S: I meas.: 152,5 ± 6,8 mm Hg vs. II meas.: 130,0 ± 8,3 mm Hg, p < 0.007); 2. significant decrease of DPP (Me ± S: I meas.: 95,0 ± 3,44 mm Hg vs. II meas.: 80,8 ± 5,74 mm Hg, p < 0.0003); 3. non-significant decrease of ET-1 concentration (Me ± S: I meas.: 110,5 ± 34,9 pg/ml vs. II meas.: 99,7 ± 21,2 pg/ml, p = 0.53); 4. non significant changes of aldosterone concentration (Me ± S: I meas.: 169,8 ± 114,1 pg/ml vs. II meas.: 162,1 ± 72,7 pg/ml, p = 0.18).
Conclusion In our investigation the administration of amlodipine 5 mg/d. not influencing RAA system (no changes in aldosterone concentration) leads to non-significant decrease of ET-1 concentration. However, small number of patients and clear trend to decrease ET-1 concentration seems to require continuation of investigation.