Isolation of prolactin from human pituitary glands: some safety aspects of an improved partial purification procedure.

Human prolactin was partially purified from pituitary glands by a combination of alkaline extraction, ammonium sulphate precipitation, hydrophobic interaction chromatography and gel filtration. The early steps in the purification were carried out under stringent safety conditions to minimise the risk of exposure to potential viral pathogens present in human tissue. Alkaline extraction was carried out over a short time interval to limit possible deamidation of prolactin without loss in recovery. During chromatography on phenyl-Sepharose, it was found that bound prolactin could be eluted with aqueous buffer, in contrast to the organic solvents used by previous investigators. Subsequent gel filtration removed high molecular weight contaminant proteins and further confirmed the monomeric form of purified prolactin. This material could be further purified to near homogeneity by ion-exchange chromatography and other separation techniques. Some guidelines on the safety precautions undertaken during the extraction of prolactin are described.