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The Effects of Calorie Restriction on Skeletal Muscle Glucose Uptake and Insulin Signaling in 24 Month‐old Rats
Author(s) -
Sequea Donel Angelo,
Sharma Naveen,
Arias Edward,
Cartee Gregory
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1077.1
Subject(s) - glut4 , medicine , endocrinology , protein kinase b , calorie restriction , insulin , phosphorylation , skeletal muscle , soleus muscle , insulin receptor , glucose uptake , irs1 , chemistry , biology , insulin resistance , biochemistry
Calorie restriction (CR; eating ~60% of ad libitum, AL, intake) enhances insulin‐mediated glucose uptake (GU) and phosphorylation of Akt (an essential signaling protein for GU) in isolated rat skeletal muscle (predominantly fast twitch epitrochlearis and predominantly slow twitch soleus) in 9 month‐old rats. The primary aim of this study was to determine if CR also improves glucose uptake in both epitrochlearis and soleus of male, Fischer 344 Brown Norway rats at 24 months of age. A secondary aim was to determine if CR enhances Akt and/or Akt's substrate AS160 (also important for GU) phosphorylation in 24 mo‐old rats. We hypothesized that CR improves insulin stimulated GU in both muscles through enhancement of Akt phosphorylation with enhanced AS160 phosphorylation. In vitro muscle incubation experiments were performed on rats at 24 months of age with or without 1.2nM insulin. CR increased insulin mediated GU in both muscles. Concomitantly, pAkt(T308 and S473) was increased with CR in both muscles. There was no diet effect observed in pAS160(T642) or in total GLUT4 in either muscle. Calorie restriction in old 24 month rats enhanced insulin stimulated GU; likely dependent on enhanced Akt phosphorylation but independent of enhanced AS160 phosphorylation on T642 in epitrochlearis and soleus muscle.