Eukaryotic initiation factors and protein synthesis after resistance exercise in rats

Peter A. Farrell, Jazmir M. Hernandez, Mark J. Fedele, Thomas C. Vary, Scot R. Kimball, Leonard S. Jefferson

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    32 Scopus citations

    Abstract

    Translational control of protein synthesis depends on numerous eukaryotic initiation factors (eIFs) and we have previously shown (Am. J. Physiol. Endocrinol. Metab. 276: E721-E727, 1999) that increases in one factor, eIF2B, are associated with increases in rates of protein synthesis after resistance exercise in rats. In the present study we investigated whether the eIF4E family of initiation factors is also involved with an anabolic response to exercise. Male Sprague-Dawley rats either remained sedentary (n = 6) or performed acute resistance exercise (n = 6), and rates of protein synthesis were assessed in vivo 16 h after the last session of resistance exercise. eIF4E complexed to eIF4G (eIF4E · eIF4G), eIF4E binding protein 1 (4E-BP1) complexed to eIF4E, and phosphorylation state of eIF4E and 4E-BP1 (γ-form) were assessed in gastrocnemius. Rates of protein synthesis were higher in exercised rats compared with sedentary rats [205 ± 8 (SE) vs. 164 ± 5.5 nmol phenylalanine incorporated.g muscle-1 · h-1, respectively; P < 0.05]. Arterial plasma insulin concentrations were not different between the two groups. A trend (P = 0.09) for an increase in eIF4E·eIF4G with exercise was noted; however, no statistically significant differences were observed in any of the components of the eIF4E family in response to resistance exercise. These new data, along with our previous report on eIF2B, suggest that the regulation of peptide chain initiation after exercise is more dependent on eIF2B than on the eIF4E system.

    Original languageEnglish (US)
    Pages (from-to)1036-1042
    Number of pages7
    JournalJournal of applied physiology
    Volume88
    Issue number3
    DOIs
    StatePublished - Mar 2000

    All Science Journal Classification (ASJC) codes

    • Physiology
    • Physiology (medical)

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