Characterization of prolactin immunoreactivity in human cerebrospinal fluid

Immunoreactive prolactin has been recovered from human cerebrospinal fluid (CSF) by hydrophobic interaction chromatography on Phenyl-Sepharose CL-4B and molecular sieving on Sephadex G-100. The hormone was obtained in a yield of about 1 microgram/liter CSF and was further analyzed by column electrophoresis on granular agarose at different pHs. All separation procedures were guided by radioimmunoassay. Upon chromatography on Sephadex G-100, the CSF prolactin coeluted with a pituitary reference preparation (molecular weight, 22,000 Da). A further relationship between the CSF prolactin and the pituitary hormone was demonstrated by the electrophoretic experiments. Thus, at alkaline pH, both preparations resolved into 3 or 4 active components, whereas only a single peak was observed in each preparation following runs performed at acidic pH. The results suggest that the prolactin activity present in the CSF specimens is identical with the hormone derived from the pituitary.