Purification and partial characterization of a liver cell proliferation factor called hepatopoietin

The purification and partial characterization of a liver cell proliferation factor called hepatopoietin are described. Hepatopoietin was isolated from remnant livers or blood plasma of partially hepatectomized rats and purified approximately 13,000-fold. The stokes radius was 2.65 +/- 0.2 nm and the apparent molecular weight was calculated to be 38,000 +/- 5,000 D. Hepatopoietin is a heat-stable glycoprotein and is organ specific but species nonspecific. In vivo it stimulates about three to four times the DNA synthesis as well as the mitotic rate of the liver of normal rats after i.p. injection. Hepatopoietin is inactivated upon incubation with galactosidase or trypsin-chymotrypsin.