Stimulating effect of blood serums from tumor-bearing rats on cholesteryl ester synthesis in normal rat liver cytosol in vitro.

Addition of diluted blood serum from tumor-bearing rats stimulated significantly the synthesis of cholesteryl esters from labeled cholesterol and endogenous fatty acids in the cytosol derived from normal rat liver. With both Zajdela and Walker transplantable tumors this effect was found to be associated with the most intensive period of tumor growth. During chemical carcinogenesis induced by a single subcutaneous administration of benzo(a)pyrene the stimulating effect of sera was found to precede several weeks the appearance of palpable tumors and persisted during the period of progressive tumor growth.