Dietary corn oil does not suppress the fructose induced increase in hepatic fatty acid synthesis

Abstract

The effect of dietary glucose and fructose on hepatic and whole body fatty acid synthesis in the presence and absence of added corn oil in the diet was examined in mice. Fructose-fed mice have higher rates of hepatic but not extra-hepatic fatty acid synthesis in vivo than do those fed glucose. In addition, fructose based diets elicit higher hepatic activities of fatty acid synthetase (FAS) ATP citrate lyase (CL), malic enzyme (ME) and glucose-6-phosphate dehydrogenase (G6PD) than do glucose based diets. Glucokinase (GK) was higher in glucose fed than fructose fed mice. Acetyl CoA carboxylase (AcCx) was the same on both diets. Inclusion of 5% corn oil in the diets decreased the activities of hepatic AcCx, FAS, ME, G6PD and in vivo hepatic and extra hepatic fatty acid synthesis in glucose fed mice but did not inhibit these in fructose fed mice except for G6PD where the inhibition was less than in glucose fed mice. Thus fructose feeding lead to higher rates of fat synthesis and less sensitivity to inhibition by dietary fat than does glucose feeding.