title: Modulation of the cellular content of metabolites in adipocytes by insulin.
abstract: Although the insulin-mediated cell signaling pathway has been extensively examined, changes in the cellular content of metabolites currently remain unclear. We herein examined metabolite contents in 3T3-L1 adipocytes treated with insulin using a metabolomic analysis. Fifty-four compounds were detected, and the contents of metabolites from the citric acid cycle increased in response to the insulin treatment for 4 h, which was sensitive to U0126 and LY294002, inhibitors for mitogen-activated protein kinase kinase-1 and phosphoinositide 3-kinase, respectively. The cellular contents of fumaric acid and malic acid were increased more by insulin than those of citric acid and succinic acid. Time-course changes in metabolites from the citric acid cycle exhibited oscillations with a 2-h cycle. A metabolic pathway analysis also indicated that insulin affected the metabolism of alanine, aspartate and glutamate, as well as that of arginine and proline. The contents of free amino acids were slightly decreased by the insulin treatment, while the co-treatment with U0126 and LY294002 abrogated these insulin-mediated decreases. The present study revealed the unexpected accumulation of citric acid cycle metabolites in adipocytes by insulin. Our results indicate the usefulness of metabolomic analyses for obtaining a more comprehensive understanding of the regulation of metabolic pathways in cell-culture systems.
authors.affiliation: Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Yuhang
authors.initials: Y
authors.lastname: Qiao
authors.affiliation: Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Shozo
authors.initials: S
authors.lastname: Tomonaga
authors.affiliation: Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan. Electronic address: mfunaba@kais.kyoto-u.ac.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Funaba
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D000596:Amino Acids / Q000187:drug effects; D000818:Animals; D002952:Citric Acid Cycle / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects; D007328:Insulin / Q000494:pharmacology*; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000187:drug effects*; D055432:Metabolomics / Q000379:methods; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism
chemical_list: D000596:Amino Acids; D007328:Insulin; D019869:Phosphatidylinositol 3-Kinases; D048369:MAP Kinase Kinase 1
keywords: Adipocyte; Citric acid; Fumaric acid; Insulin; Malic acid; Metabolome; Succinic acid