Effects of diet on rat intestinal soluble hexokinase and fructokinase activities.

WEISER,MILTON M., HELEN QUILL, AND KURT J. ISSELBACHER. effects c~f diet on rat intestinal soluble hexokinase and fructokinase activities. Am. J. Physiol. 221(3) : 844-849. 1971 .-The effects of diet on rat intestinal hexokinase activity, hexokinase isozymes, and fructokinase activity were evaluated by separation of these enzymes with DEAEcellulose chromatography. Casein noncarbohydrate diets decreased intestinal hexokinase activity when compared to starved animals. High-fructose diets did not increase hexokinase activity. High-glucose or high-sucrose diets increased hexokinase activity but only as compared to the casein-fed animals. A major effect of high-glucose diets was a relative increase in jejunal type II hexokinase over type I. The increased ratio of type 11 over trpe I hexokinase appeared to be confined to the upper absorbing cells of the villus, suggesting a noninductive effect of high-glucose concentrations. 7j6, IV (glucokinase) was never detected. Hexokinase activity w’as consistently higher in the ileum while fructokinase activity was higher in the jejunum. Starved animals and casein noncarbohydrate-fed animals had equally low fructokinase activity. All three high-carbohydrate diets (glucose, fructose, and sucrose) increased fructokinase activity, though the increase was higher on the high-fructose and high-sucrose diets.