Immunoreactive adrenomedullin in human plasma

Abstract

A specific and sensitive radioimmunoassay for adrenomedullin has been developed. Half‐maximal inhibition of binding of radioiodinated adrenomedullin was observed at 4 tool/tube. The radioimmunoassay recognized the entire adrenomedullin molecule and has little crossreactivity with adrenomedullin fragment peptides. Adrenomedullin‐like immunoreactivity was found to circulate in human plasma at considerable concentration (3.3 ± 0.39 ). The immunoreactivity of adrenomedullin was eluted at almost the same position as synthetic adrenomedullin on gel‐filtration chromatography and reverse‐phase high‐performance liquid chromatography, suggesting that circulating adrenomedullin recognized by the present radioimmunoassay is identical or very similar to authentic adrenomedullin. Plasma immunoreactive adrenomedullin significantly increased in patients with hypertension, with a progressive rise proportionate to disease severity.