Beta-endorphin-, leucine enkephalin- and methionine enkephalin-like immunoreactivity in human cerebrospinal fluid. Simultaneous determination and relation to neurological disorders.

beta-Endorphin, leucine enkephalin and methionine enkephalin, were measured in 41 samples of human lumbar cerebrospinal fluid (CSF) of patients with different neurological diseases. beta-Endorphin-like immunoreactivity (beta-ELI) was present in concentrations between 10 and 150 fmol/ml CSF, and in 30 of the 41 samples studied the levels ranged from 10 to 40 fmol/ml. Methionine enkephalin-like immunoreactivity (MELI) measured 1-85 pmol/ml CSF, with 24 of the 41 samples having values between 3 and 4 pmol/ml. CSF concentrations of leucine enkephalin-like immunoreactivity (LELI) ranged from 0.1 to 12.5 pmol/ml, and in 31 of the 41 CSF samples studied LELI was present in concentrations of 0.1-0.25 pmol/ml. No significant relationship exists between the concentrations of beta-endorphin in CSF and sex and age of patients, CSF protein, CSF IgG and CSF leukocytes. No interrelationship could be found between beta-ELI, MELI and LELI concentrations.