An inhibitor of hepatoma cells multiplication in the efferent fluid from isolated perfused rat liver.

Efferent fluid from isolated rat livers perfused with a synthetic medium, when concentrated, inhibits the multiplication of hepatoma LF 20 cells "in vitro". The inhibitory factor is thermolabile, and is inactivated at a slow rate by proteolytic enzymes. Sephadex and Acrylamide-agarose chromatographic fractionation leads us to assume a molecular weight around 100,000 for the inhibitory factor. The release of the factor by the perfused liver depends on the temperature of the perfusing fluid. Potential role of this factor in the control of liver cell proliferation is discussed.