ABSTRACT
Endothelin (ET) is an endothelium-derived vasoconstrictive peptide. We have developed a sensitive and selective radioimmunoassay for porcine/human endothelin (ET-1). 126I-labled ET was perpared by lodogen method and was purified by HPLC. Its specific activity was about 64.75 TBq(1750Ci)/mmol. The assay has a detection limit of 0.17pg/tube and the assay range was 0.25-1000pg/tube. The procedure was developed for extraction of endothelin from human plasma using C18 Sep-pak extraction cartridges. Human plasma samples were extracted, assayed and the plasma ET values of 17 healthly volunteers was found to be 2.81 ?0.60pg/ml. Both patients with uraemia(n = 20) and acute myocardial infarction(n= 11) had significantly higher plasma values than normal subjects.