Isolation of hepatocyte stimulating factor from human monocytes.

Hepatocyte stimulating factor is a monocyte derived protein which regulates hepatic plasma protein synthesis. Human hepatocyte stimulating factor was purified to apparent homogeneity from adherent peripheral blood monocytes by using ion exchange, gel permeation and reversed phase chromatography. Electrophoretic analysis showed that it has a Mr of 28,000 daltons and an isoelectric point of 5.4. Biological assays specific for hepatocyte stimulating factor and interleukin-1 showed that they are distinct and have independent biological effects.