Immunoreactive Endothelin-1 in Plasma Detected by a Sandwich-Type Enzyme Immunoassay

Summary Immunoreactive endothelin-1 (ET-1) in normal human plasma was determined by a sensitive sandwich-type enzyme immunoassay after being extracted with Seppak C18 cartridges. The average levels were 1.5 $$ 0.4 pg/ml (n = 90, range: 0.8–2.8 pg/ml) for males and 1.5 $$ 0.5 pg/ml (n = 25, range: 0.7–2.4 pg/ml) for females.