Influences of Dietary Carbohydrate-Fat Combinations on Various Functions Associated with Glycolysis and Lipogenesis in Rats

Abstract

Weanling rats were fed diets differing only in source of carbohydrate and fat for 2 to 4 weeks. Livers were assayed for glucose-6-phosphatase and fructose diphosphatase activities, and for content of glycogen and lipids. Effects on enzyme activities of substituting fructose for glucose were similar to those observed on substituting sucrose for rice starch (previous report). Feeding either hydrogenated coconut oil (HCO) or hydrogenated peanut oil (HPO) in place of corn oil (CO) modified the enzymatic responses to dietary fructose. Results with HPO were somewhat different than those with HCO. Labile phosphorus values were highest in groups fed sucrose or fructose with CO, and lowest in those fed rice starch or glucose with HPO. Effects of dietary carbohydrate on accumulation of lipid in liver appeared to be a function of the type of fat fed, namely, substitution of a fructose source for a direct glucose source resulted in the accumulation of less fat in livers of rats fed CO, but of more fat in livers of rats fed a hydrogenated oil. Proportions of phospholipid and cholesterol in liver lipid, and concentration of cholesterol in serum also varied with the combination of carbohydrate and fat fed.