Radioreceptor assay of methionine-enkephalin-like substance in human cerebrospinal fluid

Abstract

A sensitive and simple radioreceptor assay system for measuring methionine(met)-enkephalin-like substance in human CSF was developed using a particulate fraction of rat brain as a receptor preparation and [3H]dihydromorphine as a radiolabeled ligand in the presence of 1 mM EDTA and 2 mM magnesium acetate. Metenkephalin-like substance was purified from CSF by the combination of Sephadex G-10 and SP-Sephadex (H+) column chromatographies free of Na and large MW substances such as .beta.-endorphin. Assays were performed on samples obtained from normal subjects and patients with disease of the brain or pituitary by lumbar or ventricular puncture. The mean level in samples obtained from normal subjects by lumbar puncture was 2.6 .+-. 1.0 pmol/ml.