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Alteration of erythrocyte membrane Na, K‐ATPase in children with borderline or essential hypertension
Author(s) -
Stojadinovic Nataša D.,
Petronijević Milan R.,
Pavićević Mirjana H.,
Mršulja Bogomir B.,
Kostić Milosav M.
Publication year - 1996
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.652
Subject(s) - essential hypertension , medicine , atpase , endocrinology , adenylate kinase , enzyme , glutathione , erythrocyte membrane , antioxidant , chemistry , in vivo , enzyme assay , biochemistry , membrane , biology , blood pressure , microbiology and biotechnology
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 (FeSO 4 /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.