title: Relationship between (Na + K)-ATPase activity, lipid peroxidation and fatty acid profile in erythrocytes of hypertensive and normotensive subjects.
abstract: Oxidative stress may play a role in the pathogenic mechanism of essential hypertension. Lipid peroxidation can alter the cellular structure of membrane-bound enzymes by changing the membrane phospholipids fatty acids composition. We investigated the relationship between (Na + K)-ATPase activity, lipid peroxidation, and erythrocyte fatty acid composition in essential hypertension. The study included 40 essential hypertensive and 49 healthy normotensive men (ages 35-60 years). Exclusion criteria were obesity, dyslipidemia, diabetes mellitus, smoking, and any current medication. Patients underwent 24-h ambulatory blood pressure monitoring and blood sampling. Lipid peroxidation was measured in the plasma and erythrocytes as 8-isoprostane or malondialdehyde (MDA), respectively. Antioxidant capacity was measured as ferric reducing ability of plasma (FRAP) in the plasma and as reduced/oxidized glutathione (GSH/GSSG ratio) in erythrocytes. (Na + K)-ATPase activity and fatty acids were determined in erythrocyte membranes. Hypertensives had higher levels of plasma 8-isoprostane, erythrocyte MDA, and relative percentage of saturated membrane fatty acids, but lower plasma FRAP levels, erythrocyte GSH/GSSG ratio, (Na + K)-ATPase activity and relative percentage of unsaturated membrane fatty acids, compared with normotensives. Day-time systolic and diastolic blood pressures correlated positively with lipid peroxidation parameters, but negatively with (Na + K)-ATPase activity. These findings suggest that the modulation of (Na + K)-ATPase activity may be associated with changes in the fatty acid composition induced by oxidative stress and provide evidence of a role for this enzyme in the pathophysiology of essential hypertension.
authors.affiliation: Laboratory of Renal Pathophysiology, Molecular and Clinical Pharmacology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Independencia 1027, Casilla, 70058, Santiago 7, Chile. rrodrigo@med.uchile.cl
authors.forename: Ramón
authors.initials: R
authors.lastname: Rodrigo
authors.forename: Jean P
authors.initials: JP
authors.lastname: Bächler
authors.forename: Julia
authors.initials: J
authors.lastname: Araya
authors.forename: Hernán
authors.initials: H
authors.lastname: Prat
authors.forename: Walter
authors.initials: W
authors.lastname: Passalacqua
mesh_terms: D000328:Adult; D018660:Blood Pressure Monitoring, Ambulatory; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004910:Erythrocyte Membrane / Q000737:chemistry; D004912:Erythrocytes / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D006973:Hypertension / Q000378:metabolism* / Q000473:pathology; D015227:Lipid Peroxidation; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008875:Middle Aged; D018384:Oxidative Stress; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D008315:Malondialdehyde; D000254:Sodium-Potassium-Exchanging ATPase; D005978:Glutathione