Comparative Studies on the Effect of Dietary Carbohydrates on Fat Synthesis

Abstract

Rats and fish were used to study the effect of diets differing only in carbohydrate supplement on the specific activity of the enzyme acetyl coenzyme A carboxylase which catalyzes the first step in the de novo biosynthesis of lipids. The carbohydrates fed were glucose, fructose or glycerol. Glucose is metabolized in an insulin-regulated pathway while the other two sugars are not in mammals. It was found that normal rats have about the same acetyl coenzyme A carboxylase activity regardless of diet when fed for a seven day period. The marine catfish, Arius felis apparently cannot tolerate a diet containing 17.7% fructose.