Preserved protein synthesis in the heart in response to acute fasting and chronic food restriction despite reductions in liver and skeletal muscle

Celvie L. Yuan, Naveen Sharma, Danielle A. Gilge, William C. Stanley, Yi Li, Maria Hatzoglou, Stephen F. Previs

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

Whole body protein synthesis is reduced during the fed-to-fasted transition and in cases of chronic dietary restriction; however, less is known about tissue-specific alterations. We have assessed the extent to which protein synthesis in cardiac muscle responds to dietary perturbations compared with liver and skeletal muscle by applying a novel 2H2O tracer method to quantify tissue-specific responses of protein synthesis in vivo. We hypothesized that protein synthesis in cardiac muscle would be unaffected by acute fasting or food restriction, whereas protein synthesis in the liver and gastrocnemius muscle would be reduced when there is a protein-energy deficit. We found that, although protein synthesis in liver and gastrocnemius muscle was significantly reduced by acute fasting, there were no changes in protein synthesis in the left ventricle of the heart for either the total protein pool or in isolated mitochondrial or cytosolic compartments. Likewise, a chronic reduction in calorie intake, induced by food restriction, did not affect protein synthesis in the heart, whereas protein synthesis in skeletal muscle and liver was decreased. The later observations are supported by changes in the phosphorylation state of two critical mediators of protein synthesis (4E-BP1 and eIF2α) in the respective tissues. We conclude that cardiac protein synthesis is maintained in cases of nutritional perturbations, in strong contrast to liver and gastrocnemius muscle, where protein synthesis is decreased by acute fasting or chronic food restriction.

Original languageEnglish
Pages (from-to)E216-E222
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume295
Issue number1
DOIs
StatePublished - Jul 2008

Keywords

  • Calorie restriction
  • Left ventricular hypertrophy
  • Nitrogen homeostasis
  • Protein turnover
  • Stable isotopes

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