Role of eIF4E in stimulation of protein synthesis by IGF-I in perfused rat skeletal muscle

Thomas C. Vary, Leonard S. Jefferson, Scot R. Kimball

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


Insulin-like growth factor I (IGF-I) promotes anabolism by stimulating protein synthesis in skeletal muscle. In the present study, we have examined mechanisms by which IGF-I stimulates protein synthesis in skeletal muscle with a perfused rat hindlimb preparation. IGF-I (10 nM) stimulated protein synthesis over 2.7-fold. Total RNA content was unaffected, but translational efficiency was increased by IGF-I. We next examined the effect of IGF-I on eukaryotic initiation factor (eIF) 4E as a mechanism regulating translation initiation. IGF-I did not alter either the amount of eIF4E associated with the eIF4E binding protein 4E-BP1 or the phosphorylation state of 4E-BP1. Likewise, the phosphorylation state of eIF4E was unaltered by IGF-I. In contrast, the amount of eIF4E bound to eIF4G was increased threefold by IGF- I. We conclude that IGF-I regulates protein synthesis in skeletal muscle by enhancing formation of the active eIF4E·eIF4G complex.

Original languageEnglish (US)
Pages (from-to)E58-E64
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Issue number1 41-1
StatePublished - Jan 2000

All Science Journal Classification (ASJC) codes

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)


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