Variations in the composition of arterial wall isomeric chondroitin sulfate proteoglycans among different animal species.

1. Isomeric chondroitin sulfate proteoglycans were extracted from human, bovine, swine and rabbit aortas by 4 M guanidine-HCl and were fractionated and purified by CsCl isopycnic centrifugation, Sepharose CL-4B gel filtration, DEAE-Sepharose ion-exchange chromatography and octyl-Sepharose hydrophobic interaction chromatography. 2. The molecular size and the composition of isomeric chondroitin sulfate proteoglycans varied among species. Variations were also noted in the composition and molecular weight of constituent glycosaminoglycan chains. 3. Observations made on chondroitinase ABC and chondroitinase AC digests of proteoglycans indicate that dermatan sulfate is linked to the core proteins through chondroitin sulfates.

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.