Abstract
Insulin resistance is a common disorder caused by a wide variety of physiological insults, some of which include poor diet, inflammation, anti-inflammatory steroids, hyperinsulinemia, and dyslipidemia. The common link between these diverse insults and insulin resistance is widely considered to involve impaired insulin signaling, particularly at the level of the insulin receptor substrate (IRS). To test this model, we utilized a heterologous system involving the platelet-derived growth factor (PDGF) pathway that recapitulates many aspects of insulin action independently of IRS. We comprehensively analyzed six models of insulin resistance in three experimental systems and consistently observed defects in both insulin and PDGF action despite a range of insult-specific defects within the IRS-Akt nexus. These findings indicate that while insulin resistance is associated with multiple deficiencies, the most deleterious defects and the origin of insulin resistance occur independently of IRS.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing / physiology*
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Adipocytes / cytology
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Adipocytes / metabolism
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Animals
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Cells, Cultured
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Glucose Tolerance Test
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Glucose Transporter Type 4 / metabolism
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Hyperinsulinism / etiology*
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Hypoglycemic Agents / pharmacology*
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Immunoblotting
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Inflammation
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Insulin / pharmacology*
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Insulin Receptor Substrate Proteins
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Insulin Resistance*
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Male
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Mice
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Mice, Inbred C57BL
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Mice, Transgenic
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Myoblasts / cytology
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Myoblasts / metabolism
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Oxidative Stress
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Palmitates / metabolism
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Phosphatidylinositol 3-Kinases / metabolism
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Platelet-Derived Growth Factor / metabolism
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Protein Transport
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Proto-Oncogene Proteins c-akt / metabolism
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Rats
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Signal Transduction
Substances
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Adaptor Proteins, Signal Transducing
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Glucose Transporter Type 4
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Hypoglycemic Agents
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Insulin
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Insulin Receptor Substrate Proteins
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Irs1 protein, mouse
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Irs1 protein, rat
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Palmitates
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Platelet-Derived Growth Factor
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Phosphatidylinositol 3-Kinases
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Proto-Oncogene Proteins c-akt