Stojadinovic N D, Petronijević M R, Pavićević M H, Mrsulja B B, Kostić M M
Institute of Physiology, Faculty of Medicine, Clinical Hospital Centre Kragujevac, University of Kragujevac, Yugoslavia.
Cell Biochem Funct. 1996 Jun;14(2):79-87. doi: 10.1002/cbf.652.
The aim of this study was to evaluate the substrate (ATP) kinetics of erythrocyte membrane Na, K-ATPase in children with borderline or essential hypertension. Although the activity of Na, K-ATPase in the presence of in vivo concentrations of ATP was not significantly altered, kinetic studies showed an obvious inhibition of enzyme activity in the erythrocyte membrane of children with borderline or essential hypertension. Hanes plot analysis revealed a decrease of V(max) from 7.19 in erythrocytes from control subjects to 4.93 and 3.33 in those from children with borderline or essential hypertension, respectively. A mean value of the K(m) decreased from 0.10 in the control to 0.08 and 0.02 in children with borderline or essential hypertension, respectively. The energy status of erythrocytes, estimated by ATP, ADP and AMP levels, ATP/ADP ratio, and adenylate energy charge (AEC) was not significantly changed in the cells from hypertensive children. The use of a free radical-generating system (FeSO4/ascorbate) in vitro significantly reduced enzyme activity in the control erythrocytes while in those from hypertensive children it was abolished completely. The level of lipid peroxides was considerably higher (+ 37 per cent) in the plasma, while that of reduced glutathione was significantly lower both in the erythrocytes and the plasma of children with essential hypertension than in healthy children. These results indicate significant alterations of the antioxidant status which could be the cause of the inhibited Na, K-ATPase activity in erythrocyte membranes from hypertensive children.
本研究旨在评估临界高血压或原发性高血压患儿红细胞膜钠钾 - ATP酶的底物（ATP）动力学。尽管在体内ATP浓度存在时钠钾 - ATP酶的活性没有显著改变，但动力学研究表明临界高血压或原发性高血压患儿红细胞膜中的酶活性受到明显抑制。Hanes图分析显示，对照组红细胞的V(max)从7.19降至临界高血压或原发性高血压患儿红细胞的4.93和3.33。K(m)的平均值从对照组的0.10分别降至临界高血压或原发性高血压患儿的0.08和0.02。通过ATP、ADP和AMP水平、ATP/ADP比率以及腺苷酸能量电荷（AEC）估计的红细胞能量状态在高血压患儿的细胞中没有显著变化。体外使用自由基生成系统（FeSO4/抗坏血酸盐）可显著降低对照组红细胞中的酶活性，而在高血压患儿的红细胞中酶活性则完全被消除。原发性高血压患儿血浆中的脂质过氧化物水平显著更高（+ 37%），而红细胞和血浆中还原型谷胱甘肽的水平均显著低于健康儿童。这些结果表明抗氧化状态存在显著改变，这可能是高血压患儿红细胞膜中钠钾 - ATP酶活性受到抑制的原因。
