Insulin or sulfonylurea treatments of the diabetics differentially affect erythrocyte membrane and serum enzymes and extent of protein glycosylation

Erythrocyte membrane protein glycosylation increased by 3.4 fold in diabetes, insulin or sulfonylurea treatment did not reduce the extent of glycosylation. The serum protein glycosylation was comparable in all the groups including control. Erythrocyte membrane Na⁺,K⁺-ATPase activity decreased in the diabetics; only insulin treatment partly restored the activity. Erythrocyte membrane acetylcholinesterase activity decreased only in the sulfonylurea treated group. Serum butyrylcholinesterase activity was relatively low in the diabetic and insulin treated diabetic groups. The Km and Vmax of the two components of Na⁺,K⁺-ATPase from erythrocyte membranes were differently affected in the diabetic and the two treatment groups. The Vmax of acetylcholinesterase decreased only in the sulfonylurea treated group. Diabetic states resulted in decreased Vmax of components I and II of serum butyrylcholinesterase. In insulin-treated diabetics, component II was absent. Sulfonylurea group resembled diabetics. In vitro incubation with insulin differentially affected the Na⁺ K ⁺-ATPase and serum butyrylcholinesterase activities.