Effects of diabetes and high fat-high cholesterol diet on plasma lipid levels and on erythrocyte membrane composition.

Erythrocyte membrane composition was studied in rats subjected to experimental hyperlipidemia and/or hyperglycemia by means of 6 weeks of high fat (40% w/w)-high cholesterol (5% w/w)diet with and without 8 weeks of streptozotocin-induced diabetes. High fat-high cholesterol diet lowered plasma glucose levels in control and in diabetic animals. While the atherogenic diet produced only hypercholesterolemia, the same diet fed to diabetic animals produced both hypercholesterolemia and hypertriglyceridemia. The membrane protein content was lower in diabetic rats than in controls, while the cholesterol and phospholipids were higher in diabetic rat erythrocyte membranes. Feeding the atherogenic diet increased membrane lipid levels in only nondiabetic animals. The total carbohydrate content of the membranes was greater in diabetic animals than controls. Difference in relative proportion of individual sugars, e.g., galactose, mannose, glucose, and fucose of the membranes was observed between diabetic and control groups. These observations suggest that rat erythrocyte membrane composition is altered both in hyperglycemic and hyperlipidemic conditions, and may provide a useful model for evaluating lipid carbohydrate abnormalities of membrane structures in diabetes mellitus.