title: The effect of glucose concentration on insulin-induced 3T3-L1 adipose cell differentiation.
abstract: We examined the effect of glucose concentration on insulin-induced 3T3-L1 adipose cell differentiation. Oil Red O staining of neutral lipid, cellular triglyceride mass, and glycerol phosphate dehydrogenase (GPDH) activity, were greater in 3T3-L1 cells cultured at 5 mM vs. 25 mM glucose. GPDH activity was 2- to 4-fold higher at 5 mM vs. 25 mM glucose over a range of insulin concentrations (0.1 to 100 nM). Insulin-stimulated tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) was 1.7-fold greater, and insulin-stimulated phosphoinositide 3-kinase association with IRS-1 was 2.3-fold higher, at 5 mM vs. 25 mM glucose. These effects of glucose were not caused by alterations in IRS-1 mass or cell-surface insulin binding. In preadipose cells at 5 mM glucose, expression of the leukocyte antigen-related (LAR) protein tyrosine phosphatase (negative regulator of insulin signaling) was 63% of the level at 25 mM glucose. Our data demonstrate that glucose concentration affects insulin-induced 3T3-L1 adipose cell differentiation as well as differentiation-directed insulin signaling pathways. Alterations in LAR expression potentially may be involved in modulating these responses.
authors.affiliation: Ottawa Civic Hospital Loeb Research Institute, Department of Medicine, University of Ottawa, Ontario, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Gagnon
authors.forename: A
authors.initials: A
authors.lastname: Sorisky
mesh_terms: D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology* / Q000378:metabolism; D000818:Animals; D001391:Azo Compounds; D002454:Cell Differentiation / Q000187:drug effects*; D004396:Coloring Agents; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000494:pharmacology*; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D055504:Insulin Receptor Substrate Proteins; D007700:Kinetics; D050356:Lipid Metabolism; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4; D011956:Receptors, Cell Surface; D013194:Staining and Labeling; D014280:Triglycerides / Q000378:metabolism
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; D010750:Phosphoproteins; D011956:Receptors, Cell Surface; D014280:Triglycerides; D019000:Phosphotyrosine; D005993:Glycerolphosphate Dehydrogenase; D019869:Phosphatidylinositol 3-Kinases; D017027:Protein Tyrosine Phosphatases; C516843:Ptpra protein, mouse; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4; C011049:oil red O; D005947:Glucose