Rabini R A, Galassi R, Staffolani R, Vasta M, Fumelli P, Mazzanti L
Department of Diabetology, Italian National Research Center on Aging, Ancona.
Diabetes Res. 1993;22(1):33-40.
Several plasma membrane alterations have been described in diabetes mellitus. Data reported in gestational diabetes mellitus (GDM) suggested that these alterations might be present before the onset of overt metabolic derangement. On the basis of these data it is tempting to hypothesize that the reduction in the sodium pump activity might be due to a genetic factor acting at the membrane level before the onset of diabetes. In order to verify this hypothesis 11 insulin-dependent diabetic patients, 15 first degree relatives of the patients and 10 healthy subjects with a negative family history for diabetes mellitus were studied. Fluidity, Na+/K(+)-ATPase activity and membrane cholesterol content (C) were evaluated on plasma membranes obtained from red blood cells (RBCs). Na+/K(+)-ATPase activity was reduced with a contemporary increase in membrane fluidity in RBCs from IDDM patients in comparison to either relatives and controls. The same alterations were observed also in RBCs from the relatives in comparison to controls. We did not find any significant difference in the C content among the three groups. Data herein reported provide evidence that a reduction in the Na+/K(+)-ATPase activity is present in the plasma membrane of relatives of diabetic subjects. Furthermore, the present work suggests that the change in enzymatic activity might be related to modifications in membrane fluidity.
糖尿病患者中已发现几种质膜改变。妊娠期糖尿病（GDM）的相关数据表明，这些改变可能在明显的代谢紊乱发作之前就已存在。基于这些数据，很容易推测钠泵活性降低可能是由于糖尿病发作前在膜水平起作用的遗传因素所致。为了验证这一假设，我们研究了11名胰岛素依赖型糖尿病患者、15名患者的一级亲属以及10名糖尿病家族史阴性的健康受试者。对从红细胞（RBC）获得的质膜进行了流动性、Na+/K(+)-ATP酶活性和膜胆固醇含量（C）的评估。与亲属和对照组相比，IDDM患者红细胞中的Na+/K(+)-ATP酶活性降低，同时膜流动性增加。与对照组相比，亲属的红细胞中也观察到了相同的改变。我们发现三组之间的C含量没有任何显著差异。本文报道的数据提供了证据，表明糖尿病患者亲属的质膜中存在Na+/K(+)-ATP酶活性降低。此外，目前的研究表明酶活性的变化可能与膜流动性的改变有关。
