[A method of isolating inhibitors of the proliferative activity of liver hepatocytes].

A fraction containing two tissue specific regulators of the mitotic activity (chalone) and having a definite capacity to inhibit the DNA synthesis (G1-inhibitor) and to enter into the mitosis (G2-inhibitor) of hepatocytes of the regenerating liver was isolated from an aqueous extract by ethanol saturation from 70 to 81%. The fraction contains up to 10 substances of protein nature, 7 of which, due to the data of immunological analysis, are also present in other tissues and blood serum of rats.