Presence of endothelin-1-like immunoreactivity in human cerebrospinal fluid

By use of radioimmunoassay (RIA) specific for endothelin-1 (ET-1), we have studied whether ET-1-like immunoreactivity (LI) exists in human cerebrospinal fluid (CSF). Human CSF from patients with old cerebrovascular disease contained far greater amounts of ET-1-LI (28 +/- 1.3 pg/ml, n = 9) than normal human plasma. Reverse-phase HPLC coupled with ET-1 RIA revealed a single major ET-1-LI component in human CSF extract coeluting with standard ET-1. These data suggest ET-1 is a neuropeptide secreted from neural tissues in humans.