Evaluation of urine endothelin-1 (ET-1) level in patients with essential hypertension

Abstract

Background Endothelin-1 (ET-1) as the most potent vasoconstrictor substance may play an important role in pathogenesis of arterial hypertension. These biological effects of ET-1 may indicate the logical relationship between increased ET-1 concentration and the presence of systemic hypertension. Researches do not reveal reliable information about plasma ET-1 levels in hypertensive patients. On the base of these data we may suspect that evaluation of ET-1 concentration in urine (beside cell culture) may be more precise that evaluation of this peptide in the plasma.
The aim of our study was to estimate the diagnostic value of plasma and urine ET-1 concentration measurement in hypertensive patients.
Material and methods Two groups were studied: group I - 26 hypertensive patients (systolic blood pressure: Me 158 ± 9 mm Hg, diastolic blood pressure: Me 95 ± 5 mm Hg) and group II - 10 healthy volunteers (systolic blood pressure: 120 ± 4,00 mm Hg, diastolic blood pressure: Me 68 ± 4,50 mm Hg). In classifying subjects ET-1 concentrations were measured by radioimmunoassay in: a) plasma, b) 24-hour urine collection.
Results 1. Plasma ET-1 concentration did not differ between the two groups (Me ± S group I: 37,4 ± 11,4 vs. group II: 33,3 ± 6,66 pg/ml, NS). 2. Urine ET-1 excretion assessed in 24-hour urine collection were significantly higher in I group than in II group (Me ± S group I: 106,11 ± 49,74 vs. group II: 11,3 ± 6,65 ng/g urinary creatinine, p = 0.00001).
Conclusions We may suspect that evaluation of ET-1 concentration in 24-hour urine collection may be more exact than evaluation of this peptide in plasma. This observation may prove the importance of ET-1 in hypertension.