Abstract
Phosphatidic acid (PA) dose-dependently induced superoxide (O2-) production of electropermeabilized human neutrophils but not of intact neutrophils, indicating that PA induces the activation of NADPH oxidase by acting on an intracellular target. The O2- production by PA was not inhibited by protein kinase C (PKC) inhibitors, such as staurosporine and calphostin C, and an inhibitor of PA phosphohydrolase, propranolol. These observations suggest that the activation of the oxidase by PA is independent of the activity of PKC and may dominate the activation by diacylglycerol which is formed from PA via the action of PA phosphohydrolase. Furthermore, the production by PA, as well as that by phorbol myristate acetate, was inhibited by cyclic AMP and GDP beta S. Therefore, PA seems to act at a site downstream of PKC.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Cell Membrane Permeability
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Cyclic AMP / pharmacology
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Enzyme Activation / drug effects
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Guanosine Diphosphate / analogs & derivatives
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Guanosine Diphosphate / pharmacology
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Humans
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NADH, NADPH Oxidoreductases / metabolism
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NADPH Oxidases
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Neutrophils / drug effects*
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Neutrophils / metabolism
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Phosphatidic Acids / antagonists & inhibitors
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Phosphatidic Acids / pharmacology*
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Protein Kinase C / antagonists & inhibitors
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Protein Kinase C / metabolism*
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Respiratory Burst / drug effects*
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Superoxides / metabolism
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Tetradecanoylphorbol Acetate / pharmacology
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Thionucleotides / pharmacology
Substances
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Phosphatidic Acids
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Thionucleotides
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Superoxides
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Guanosine Diphosphate
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guanosine 5'-O-(2-thiodiphosphate)
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Cyclic AMP
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NADH, NADPH Oxidoreductases
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NADPH Oxidases
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Protein Kinase C
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Tetradecanoylphorbol Acetate