Erythrocyte Ca, Na/K-ATPase in Long-TermStreptozotocin Diabetic Rats

This study evaluated the effect of chronic hyperglycemia on erythrocyte membrane Ca and Na/KATPase activities in streptozotocin-induced diabetic rats. The activity of Ca-ATPase was significantly lower in diabetic than in normal rats. Good glycemic control by insulin restored the Ca-ATPase activity to normal. By contrast, diltiazem, a calcium entry blocker, had no effect on the enzyme activity. Calmodulin stimulated Ca-ATPase activity in all groups of rats. Na/K-ATPase activity was not altered in diabetic rats, and no effects of either insulin or diltiazem treatments were observed. The results suggest that erythrocyte Ca-ATPase activity is decreased in diabetic rats and is normalized by good glycemic control. Am J Hypertens 1992;5:863-868