title: Measurement of plasma endothelin-1 in experimental hypertension and in healthy subjects.
abstract: BACKGROUND
  Endothelin-1 is an endothelium-derived potent vasoconstrictor peptide of 21 amino acids. To establish reference values in different models of hypertension and in human subjects an assay for plasma immunoreactive endothelin-1 (ET-1) was optimized.
  
  
  METHODS
  ET-1 is extracted by acetone from 1 mL of plasma and subjected to a sensitive enzyme-linked immunosorbent assay.
  
  
  RESULTS
  The detection limit for plasma ET-1 is 0.05 fmol/mL. Mean recoveries of the 1, 2, 5, and 10 fmol of ET-1 added to 1 mL of plasma were 66%, 75%, 85%, and 92%, respectively. Within- and between-assay coefficients of variation were < or =12% and < or =10%, respectively. Assay accuracy was demonstrated by consistent recoveries of added ET-1 over the entire physiologic range of plasma concentrations and by the linearity of ET-1 concentrations measured in serially diluted plasma extracts (r = 0.99). No ET-1 was detected when albumin buffer was extracted instead of plasma. Using this method, we found increased ET-1 levels in plasma of three experimental rat models of hypertension: stroke prone spontaneously hypertensive rats (SP-SHR), deoxycorticosterone acetate-salt hypertensive rats, and one kidney-one clip hypertensive rats. In contrast, plasma ET-1 levels of SHR were half those of normotensive Wistar rats. In two kidney-one clip hypertensive rats, plasma ET-1 concentrations were not different from those found in sham-operated control rats. Plasma ET-1 concentrations of 37 healthy men were 0.85 +/- 0.26 fmol/ml (mean +/- SD).
  
  
  CONCLUSIONS
  The present assay reliably measures ET-1 levels in rat and human plasma. It allows to discriminate between different forms of hypertension with high or low circulating levels of ET-1.
authors.affiliation: Division of Hypertension and Vascular Medicine, University Hospital Lausanne, Lausanne, Switzerland.
authors.forename: Saad
authors.initials: S
authors.lastname: Abdel-Sayed
authors.forename: Juerg
authors.initials: J
authors.lastname: Nussberger
authors.forename: Jean François
authors.initials: JF
authors.lastname: Aubert
authors.forename: Peter
authors.initials: P
authors.lastname: Gohlke
authors.forename: Hans Rudolf
authors.initials: HR
authors.lastname: Brunner
authors.forename: Noureddine
authors.initials: N
authors.lastname: Brakch
mesh_terms: D000818:Animals; D019332:Endothelin-1 / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D006973:Hypertension / Q000097:blood*; D008297:Male; D023421:Models, Animal; D051381:Rats; D017208:Rats, Wistar
chemical_list: D019332:Endothelin-1