Endothelin profile in essential hypertension.

Background: Patients with Essential Hypertension have been found to have elevated plasma levels of Endothelin. Objectives: To evaluate the contribution of Endothelin to blood pressure regulation in patients with Essential Hypertension by studying their plasma Endothelin profile. Methods: The study included 50 patients with essential hypertension with a mean age of 52.4±2.1 years. The control group consisted of 25 healthy subjects (mean age, 49.7±2.7 years) Plasma immunoreactive levels of Endothelin (ET-1) were determined by sensitive Enzyme-linked Immunosorbant assay (ELISA). The detection limit for Plasma Endothelin was 1.5pg/ml. Within and between assay coefficients of variation were less than 10%. Assay accuracy was demonstrated by consistent recovery of added ET-1 over the entire physiologic range of Plasma concentration and by the linearity of ET-1 concentration measured in serially diluted plasma extracts. Results: The mean (±SE) plasma Endothelin concentration was 6.0±4.0 pg/ml in normal subjects, with no correlation to age and plasma (P=0.421). In patients with essential hypertension, the mean plasma Endothelin concentration was 11.8±0.6pg/ml; significant correlation was observed between plasma Endothelin and the stage of hypertension (P=0.001) Conclusions: Plasma Endothelin levels are elevated in patients with essential hypertension compared to normal subjects; suggesting that Endothelin is relevant in the development and maintenance of elevated blood pressure. This Pathophysiologic importance of Endothelin in essential hypertension may help in future development of new drugs (Endothelin Receptor Blockers) for optimal management of these patients