Presence of immunoreactive endothelin in human milk

Abstract
Endothelin‐like immunoreactivity was detected in human milk at a concentration of 6.8 ± 1.6 (mean ± SEM; n = 16) using a highly sensitive radioimmunoassay. Gel filtration and fast protein liquid chromatography (FPLC) verified the identity of the endothelin. FPLC revealed 4 peaks, one eluting just after the void volume, and the other three in the positions of endothelin‐1, ‐2, and ‐3, respectively.