AJP - Gastrointestinal and Liver Physiology, Vol 249, Issue 5 634-G641, Copyright © 1985 by American Physiological Society
Effect of glucose or fructose feeding on cholesterol synthesis in diabetic animals
K. R. Feingold and A. H. Moser
Previous studies have demonstrated that cholesterol synthesis is increased
twofold in the small intestines of rats with streptozotocin-induced
diabetes. The purpose of the present study was to determine the effect of
adding glucose or fructose to standard rat chow on cholesterol synthesis in
control and diabetic rats. In control rats a 25% glucose or fructose diet
fed for 21 days markedly inhibited hepatic cholesterol synthesis in the
liver. In contrast, in diabetic animals only fructose inhibited hepatic
cholesterol synthesis. In both control and diabetic animals the addition of
these simple sugars to the diet did not markedly alter extrahepatic
cholesterol synthesis. The enhancement of small intestinal cholesterol
synthesis observed in diabetic animals was present regardless of the
dietary manipulations. Further studies demonstrated that the addition of
smaller concentrations of fructose (10%) to standard rat chow decreased
hepatic cholesterol synthesis in both control and diabetic rats. Similarly
the addition of fructose to the diet of control and diabetics for a period
as short as 2 days was also sufficient to inhibit hepatic cholesterol
synthesis. In both control and diabetic animals, fructose feeding decreased
hepatic 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity
but did not alter the percentage of HMG-CoA reductase in the active form.
Finally, the intestinal hypertrophy and stimulation of intestinal
cholesterogenesis that are characteristic of streptozotocin-induced
diabetes occurred when either glucose or fructose was the sole caloric
source.
