Immunoreactive β-Endorphin in Human Cerebrospinal Fluid*

Abstract

To elucidate the nature of .beta.-endorphin-like immunoreactivity in human CSF and its relationship with plasma .beta.-endorphin, plasma and CSF specimens were obtained simultaneously. Gel chromatography revealed that .beta.-endorphin-like immunoreactivity in CSF consisted of 2 components with elution positions compatible to those of .beta.-endorphin and .beta.-lipotropin (.beta.-LPH), respectively, and an additional larger molecule. The .beta.-endorphin level in CSF obtained from 4 nonendocrine patients was 17.9 .+-. 2.3 pg/ml (mean .+-. SE) and corresponded to 20% of .beta.-endorphin-like immunoreactivity. The predominant component in CSF was either .beta.-LPH or the larger molecule. .beta.-Endorphin levels in CSF were consistently higher than those in plasma and there seemed to be no relationship between them. One patient with Nelson''s syndrome had a CSF .beta.-endorphin level of 14.8 pg/ml, although the plasma level was 784 pg/ml. One patient under glucocorticoid [prednisolone] treatment had a CSF .beta.-endorphin level of 13.0 pg/ml and an undetectably low plasma level. .beta.-Endorphin-like immunoreactivity consists of .beta.-endorphin, .beta.-LPH and possibly the precursor molecule; marked dissociation exists between plasma and CSF .beta.-endorphin levels, suggesting the possible CNS origin of .beta.-endorphin in CSF.