Kiziltunç A, Akçay F, Polat F, Kuşkay S, Sahin Y N
Department of Biochemistry, Atatürk University, School of Medicine, Erzurum-Turkey.
Clin Biochem. 1997 Mar;30(2):177-82. doi: 10.1016/s0009-9120(96)00156-7.
To investigate the plasma concentrations of lecithin:cholesterol acyltransferase (LCAT EC 2.3.1.43) and erythrocyte membrane Na+, K+, ATPase and the correlation of these parameters in diabetes mellitus.
Na+, K+, ATPase was measured with spectrophotometric method and LCAT with radioactive method in 19 patients with insulin-dependent diabetes mellitus (IDDM), in 20 with non-insulin-dependent diabetes mellitus (NIDDM) and in 20 healthy volunteers as the control group.
Compared with the control group, plasma LCAT concentrations were found to be decreased in both of the patient groups (p < 0.01 for both). Erythrocyte membrane Na+, K+, ATPase activities were higher in the controls than both in the NIDDM and IDDM groups (p < 0.01 and p < 0.001, respectively). There were significant correlations between LCAT and Na+, K+, ATPase in IDDM (r = 0.82, p < 0.001) and in NIDDM (r = 0.74, p < 0.001). In order to investigate the effect of cholesterol (C) and lysophosphatidylcholine (LPC) on Na+, K+, ATPase activity, this enzyme's activity was determined in erythrocyte membranes obtained from diabetic subjects after in vitro incubation with increasing concentrations of LPC and C (2-10 microM). Enzymatic activity was significantly reduced by in vitro C at increasing concentrations but significantly increased by in vitro LPC at increasing concentrations.
From these data, it is to be concluded that the decrease in Na+, K+, ATPase activity in diabetes might be due to decreased LCAT concentrations and that may explain the development of atherosclerosis in diabetics.
研究糖尿病患者血浆卵磷脂胆固醇酰基转移酶（LCAT，EC 2.3.1.43）浓度、红细胞膜钠钾ATP酶及其参数之间的相关性。
采用分光光度法测定19例胰岛素依赖型糖尿病（IDDM）患者、20例非胰岛素依赖型糖尿病（NIDDM）患者及20名健康志愿者（对照组）的红细胞膜钠钾ATP酶活性，采用放射性方法测定LCAT活性。
与对照组相比，两组患者血浆LCAT浓度均降低（两组均P<0.01）。对照组红细胞膜钠钾ATP酶活性高于NIDDM组和IDDM组（分别为P<0.01和P<0.001）。IDDM组（r=0.82，P<0.001）和NIDDM组（r=0.74，P<0.001）中LCAT与钠钾ATP酶之间存在显著相关性。为研究胆固醇（C）和溶血磷脂酰胆碱（LPC）对钠钾ATP酶活性的影响，用浓度递增的LPC和C（2-10 microM）对糖尿病患者红细胞膜进行体外孵育后，测定该酶活性。体外C浓度递增时酶活性显著降低，而体外LPC浓度递增时酶活性显著升高。
从这些数据可以得出结论，糖尿病患者钠钾ATP酶活性降低可能是由于LCAT浓度降低所致，这可能解释了糖尿病患者动脉粥样硬化的发生。
