Abstract
The role of PI 3-kinase in transferrin receptor recycling was investigated in 3T3-L1 adipocytes. Wortmannin, a specific PI 3-kinase inhibitor, blocked insulin stimulated recruitment of transferrin receptors to the plasma membrane (IC50 approximately 5-15 nM) with a similar potency to its inhibitory effects on PI 3-kinase and glucose transport. Wortmannin also blocked insulin stimulated recruitment of IGF-2 receptors to the cell surface. However, wortmannin (up to 200 nM) and another PI 3-kinase inhibitor, LY294002 (3 micrograms/ml), did not block transferrin receptor endocytosis. This demonstrates that while PI 3-kinase may be necessary for insulin stimulated exocytosis, it is not necessary for endocytosis of transferrin receptors.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3T3 Cells
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Adipocytes / cytology
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Adipocytes / drug effects
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Adipocytes / metabolism*
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Androstadienes / pharmacology*
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Animals
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Cell Differentiation
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Cell Membrane / drug effects
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Cell Membrane / metabolism
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Chromones / pharmacology*
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Endocytosis / drug effects*
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Enzyme Inhibitors / pharmacology
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Exocytosis / drug effects*
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Glucose / metabolism
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Insulin / pharmacology
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Kinetics
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Mice
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Morpholines / pharmacology*
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Phosphatidylinositol 3-Kinases
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Phosphotransferases (Alcohol Group Acceptor) / antagonists & inhibitors*
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Receptor, IGF Type 2 / drug effects
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Receptor, IGF Type 2 / metabolism
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Receptors, Transferrin / drug effects
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Receptors, Transferrin / metabolism*
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Wortmannin
Substances
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Androstadienes
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Chromones
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Enzyme Inhibitors
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Insulin
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Morpholines
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Receptor, IGF Type 2
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Receptors, Transferrin
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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Phosphatidylinositol 3-Kinases
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Phosphotransferases (Alcohol Group Acceptor)
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Glucose
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Wortmannin