Radio-immunoassay of endothelin in human plasma
- 1 November 1991
- journal article
- research article
- Published by Taylor & Francis in Scandinavian Journal of Clinical and Laboratory Investigation
- Vol. 51 (7) , 615-623
- https://doi.org/10.3109/00365519109104572
Abstract
Endothelin (ET) is a newly described endothelium-derived 21-amino-acid peptide with potent vasoconstrictive properties. The present study describes a radio-immunoassay utilizing an antibody without cross-reactivity with big endothelin, produced after immunization of rabbits with endothelin-1 (ET-1). Measurement of endothelin in human plasma was performed after prior extraction on Sep-pak C18 cartridges. Recovery of unlabelled endothelin-1 added to human plasma (3.5 pg ml-1) was 84.8 ± 11.1% (mean ± SD, n=12). The minimum detectable level in plasma was 50 fmol l-1. High-pressure liquid chromatography on reverse-phase C18 column established that the measured irET eluted identically to ET-1. The concentration of irET in plasma from healthy control subjects was 1.11 ± 0.2 pmol-1 (mean ± SD, n=30). Agarose electrophoresis of plasma with [125I]-ET-1 indicated a reversible binding to albumin. It is concluded that ET-1 is present in measurable amounts in human plasma. It is suggested that ET-1 in plasma is associated with albumin. The importance of an adequate extraction procedure is stressed.Keywords
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