Insulin stimulates expression of the pyruvate kinase M gene in 3T3-L1 adipocytes

Yuuki Asai, Kazuya Yamada, Toyoaki Watanabe, Wee-Keong Vincent Keng, Tamio Noguchi

Research output: Journal article publicationJournal articleAcademic researchpeer-review

18 Citations (Scopus)


M2-type pyruvate kinase (M2-PK) mRNA is produced from the PKM gene by an alternative RNA splicing in adipocytes. We found that insulin increased the level of M2-PK mRNA in 3T3-L1 adipocytes in both time- and dose-dependent manners. This induction did not require the presence of glucose or glucosamine in the medium. The insulin effect was blocked by pharmacological inhibitors of insulin signaling pathways such as wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K), and PD98059, an inhibitor of mitogen-activated protein kinase (MAPK) kinase. A stable reporter expression assay showed that the promoter activity of an about 2.2-kb 5′-flanking region of the rat PKM gene was stimulated by insulin, but the extents of these stimulations were lower than those of the mRNA stimulation. Thus, we suggest that insulin increases the level of M2-PK mRNA in adipocytes by acting at transcriptional and post-transcriptional levels through signaling pathways involving both PI3K and MAPK kinase.
Original languageEnglish
Pages (from-to)1272-1277
Number of pages6
JournalBioscience, Biotechnology and Biochemistry
Issue number6
Publication statusPublished - 1 Jan 2003
Externally publishedYes


  • 3T3-L1 adipocytes
  • Insulin
  • Mitogen-activated protein kinase kinase
  • Phosphatidylinositol 3-kinase
  • Pyruvate kinase M gene

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biotechnology
  • Biochemistry
  • Applied Microbiology and Biotechnology
  • Molecular Biology
  • Organic Chemistry


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