Abstract
In this study, cell permeable diacylglycerols, sn-1,2-dioctanoglycerol (DiC8), and sn-1-oleoyl-2-acetylglycerol (OAG) were found to downregulate the activity of Na(+)-K+ pump in Xenopus laevis oocytes. Both DiC8 and OAG decreased the binding of [3H]ouabain to intact oocytes while phorbol esters did not appreciably influence the same. These diacylglycerols inhibited the amiloride-sensitive 22Na+ influx and ouabain-sensitive 86Rb+ uptake in the oocytes. Furthermore, DiC8 prevented the 22Na+ efflux from the oocytes preloaded with 22Na+. Addition of H-7 to DiC8- and OAG-treated oocytes stimulated the pump activity curtailed by the two latters. The impairment of Na(+)-K+ pump activity by diacylglycerols suggests that protein kinase C activators may stimulate endocytosis of membrane-coupled Na(+)-K+ ATPase.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
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Amiloride / pharmacology
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Animals
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Biological Transport, Active / drug effects
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Cell Membrane / enzymology
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Diglycerides / pharmacology*
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Female
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In Vitro Techniques
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Isoquinolines / pharmacology
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Kinetics
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Oocytes / drug effects
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Oocytes / metabolism*
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Piperazines / pharmacology
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Protein Kinase C / antagonists & inhibitors
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Protein Kinase C / metabolism
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Rubidium / metabolism
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Sodium / metabolism*
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Sodium-Potassium-Exchanging ATPase / metabolism*
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Tetradecanoylphorbol Acetate / pharmacology
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Xenopus laevis
Substances
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Diglycerides
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Isoquinolines
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Piperazines
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1,2-dioctanoylglycerol
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Amiloride
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1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
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1-oleoyl-2-acetylglycerol
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Sodium
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Protein Kinase C
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Sodium-Potassium-Exchanging ATPase
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Rubidium
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Tetradecanoylphorbol Acetate