Control of lipid metabolism in hepatomas: insensitivity of rate of fatty acid and cholesterol synthesis by mouse hepatoma BW7756 to fasting and to feedback control.

Abstract

We have measured the conversion of the 14C of acetate-1-14C to CO2, fatty acids, and cholesterol by slices of liver and the transplantable hepatoma BW7756, from C57L/J mice on a variety of diets: chow, fasting, refed, fat-free, high-fat, and high-cholesterol. Whereas synthesis by liver differed greatly between animals on different diets (even as much as 17-fold for fatty acid synthesis and 19-fold for cholesterol synthesis, but more generally 4- to 5-fold), synthesis by the tumor was unaffected. Although the actual mechanisms of normal dietary control of hepatic lipogenesis are not clearly known, we suggest that the insensitivity of the hepatoma to the nutritional state of the animal may be due to inability of the particular activator(s) or inhibitor(s) to gain entry into the tumor cell.