title: A sensitive radioimmunoassay measuring endothelin-like immunoreactivity in human plasma: comparison of levels in patients with essential hypertension and normotensive control subjects.
abstract: 1. A radioimmunoassay has been developed for measuring endothelin-like immunoreactivity in human plasma using an antibody raised against endothelin-1 which also cross-reacts with big endothelin-1 and endothelin-2 but not endothelin-3. 2. The sensitivity of the assay was 1 fmol/tube with inter- and intra-assay coefficients of variation of 13% and 9%, respectively. Cross-reactivity with endothelin-3 and non-endothelin peptides was less than 1%. 3. Endothelin-like immunoreactivity was present in the plasma of hypertensive patients (n = 25) at a concentration of 5.7 +/- 0.5 pmol/l (mean +/- SEM), which was not significantly different from that of age-matched control subjects (5.1 +/- 0.5 pmol/l). At these levels, endothelin-1 is unlikely to function as a circulating hormone. 4. Within the normotensive group, the concentration of endothelin-like immunoreactivity in plasma was positively correlated with mean arterial blood pressure, but in hypertensive patients it showed a significant negative correlation.
authors.affiliation: Department of Medicine, University of Cambridge, Addenbrooke's Hospital, U.K.
authors.forename: A P
authors.initials: AP
authors.lastname: Davenport
authors.forename: M J
authors.initials: MJ
authors.lastname: Ashby
authors.forename: P
authors.initials: P
authors.lastname: Easton
authors.forename: S
authors.initials: S
authors.lastname: Ella
authors.forename: J
authors.initials: J
authors.lastname: Bedford
authors.forename: C
authors.initials: C
authors.lastname: Dickerson
authors.forename: D J
authors.initials: DJ
authors.lastname: Nunez
authors.forename: S J
authors.initials: SJ
authors.lastname: Capper
authors.forename: M J
authors.initials: MJ
authors.lastname: Brown
mesh_terms: D000328:Adult; D003429:Cross Reactions; D016232:Endothelins; D004730:Endothelium, Vascular / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000097:blood* / Q000276:immunology; D011863:Radioimmunoassay; D012680:Sensitivity and Specificity
chemical_list: D016232:Endothelins; D010455:Peptides