Depression of membrane-bound Na sup + -K sup + -ATPase activity induced by free radicals and by ischemia of kidney

Journal Article · Mon Feb 01 04:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:6871524

Kako, K; Kato, M; Matsuoka, T; Mustapha, A ^[1]

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1. Univ. of Ottawa, Ontario (Canada)

A partially purified, membrane-bound Na{sup +}-K{sup +}-ATPase fraction, prepared from the outer medulla of porcine kidney, was incubated in the presence of 0.1-100 mM H{sub 2}O{sub 2} for either 15 or 30 min at 37{degree}C. The activity of ouabain-sensitive Na{sup +}-K{sup +}-ATPase was reduced proportionally to the concentration of H{sub 2}O{sub 2} and the duration of incubation. There were decreases in SH contents and turnover rates of the Na{sup +}-K{sup +}-ATPase preparation, while malondialdehyde (MDA) and conjugated dienes were generated from the membrane lipids in the course of the incubation. The concentrations of ethanolamine (E) plasmalogen and of arachidonic acid in the E glycerophospholipid molecules were reduced by the free radical reaction. Similarly, a reduction in Na{sup +}K{sup +}-ATPase activity and the formation of MDA and conjugated dienes, together with a decrease in E glycerophospholipids, were observed when the membrane fraction was exposed to ultraviolet irradiation (254 nm) for 30 min at 4{degree}C. Microsomal fractions, prepared from the outer medulla of canine kidney after 1 h of unilateral ischemia and 1 h of reperfusion, showed a decreased Na{sup +}-K{sup +}-ATPase activity, a reduced amount of SH groups, and an increased MDA. These changes were normalized by the infusion of N-mercaptopropionylglycine. These results support the view (1) that free radical generation affects the enzyme protein as well as membrane lipids, and (2) that free radicals may be formed in the ischemic reperfused kidney.

• OSTI ID: 6871524
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 254:2; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ANIMAL TISSUES
ATP-ASE
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BODY
CARBOHYDRATES
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR DISEASES
CELL CONSTITUENTS
CHROMATOGRAPHY
DISEASES
DRUGS
ELECTROMAGNETIC RADIATION
ENZYME ACTIVITY
ENZYMES
ESTERS
EXTREME ULTRAVIOLET RADIATION
GLYCOSIDES
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
HYDROLASES
HYDROXYL RADICALS
ISCHEMIA
KIDNEYS
LIPIDS
MEMBRANES
MICROSOMES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
ORGANS
OUABAIN
OXYGEN COMPOUNDS
PERFUSED TISSUES
PEROXIDES
PHOSPHOHYDROLASES
PHOSPHOLIPIDS
RADIATION EFFECTS
RADIATIONS
RADICALS
RIBOSOMES
SEPARATION PROCESSES
STROPHANTHINS
THIN-LAYER CHROMATOGRAPHY
TISSUES
TRITIUM COMPOUNDS
ULTRAVIOLET RADIATION
VASCULAR DISEASES