The vanadyl (VO2+) chelate bis(acetylacetonato)oxovanadium(IV) potentiates tyrosine phosphorylation of the insulin receptor

J Biol Inorg Chem. 2005 Dec;10(8):874-86. doi: 10.1007/s00775-005-0037-x. Epub 2005 Oct 19.


We have compared the insulin-like activity of bis(acetylacetonato)oxovanadium(IV) [VO(acac)2], bis(maltolato)oxovanadium(IV) [VO(malto)2], and bis(1-N-oxide-pyridine-2-thiolato)oxovanadium(IV) [VO(OPT)2] in differentiated 3T3-L1 adipocytes. The insulin-like influence of VO(malto)2 and VO(OPT)2 was decreased compared with that of VO(acac)2. Also, serum albumin enhanced the insulin-like activity of all three chelates more than serum transferrin. Each of the three VO2+ chelates increased the tyrosine phosphorylation of proteins in response to insulin, including the beta-subunit of the insulin receptor (IRbeta) and the insulin receptor substrate-1 (IRS1). However, VO(acac)2 exhibited the greatest synergism with insulin and was therefore further investigated. Treatment of 3T3-L1 adipocytes with 0.25 mM VO(acac)2 in the presence of 0.25 mM serum albumin synergistically increased glycogen accumulation stimulated by 0.1 and 1 nM insulin, and increased the phosphorylation of IRbeta, IRS1, protein kinase B, and glycogen synthase kinase-3beta. Wortmannin suppressed all of these classical insulin-signaling activities exerted by VO(acac)2 or insulin, except for tyrosine phosphorylation of IRbeta and IRS1. Additionally, VO(acac)2 enhanced insulin signaling and metabolic action in insulin-resistant 3T3-L1 adipocytes. Cumulatively, these results provide evidence that VO(acac)2 exerts its insulin-enhancing properties by directly potentiating the tyrosine phosphorylation of the insulin receptor, resulting in the initiation of insulin metabolic signaling cascades in 3T3-L1 adipocytes.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3-L1 Cells
  • Adipocytes / drug effects
  • Adipocytes / metabolism
  • Animals
  • Chelating Agents / pharmacology*
  • Enzyme Activation
  • Glycogen / biosynthesis
  • Glycogen Synthase / drug effects
  • Glycogen Synthase / metabolism
  • Hypoglycemic Agents / pharmacology*
  • Insulin Resistance
  • Mice
  • Molecular Structure
  • Organometallic Compounds / pharmacology
  • Phosphorylation
  • Pyrones / pharmacology
  • Receptor, Insulin / drug effects*
  • Receptor, Insulin / metabolism
  • Solutions / chemistry
  • Tyrosine / metabolism
  • Vanadates / pharmacology


  • Chelating Agents
  • Hypoglycemic Agents
  • Organometallic Compounds
  • Pyrones
  • Solutions
  • bis(1-N-oxide-pyridine-2-thiolato)oxovanadium(IV)
  • bis(acetylacetonato)oxovanadium(IV)
  • bis(maltolato)oxovanadium(IV)
  • Vanadates
  • Tyrosine
  • Glycogen
  • Glycogen Synthase
  • Receptor, Insulin