title: High-protein diets differentially modulate protein content and protein synthesis in visceral and peripheral tissues in rats.
abstract: OBJECTIVE
  High-protein diets give rise to increased amplitude in the diurnal cycling of protein gains and losses at the whole-body level, but the tissue localization and mechanisms underlying these metabolic adaptations remain unclear. We investigated tissue-specific responses to increasing protein intakes in rats.
  
  
  METHODS
  Protein synthesis rates (flooding dose with (13)C-valine) and accretion were assessed in individual tissues of fasted or fed rats (n = 32) after a 2-wk adaptation to a normal- or high-protein (HP) diet.
  
  
  RESULTS
  In livers of HP rats, a strong inhibition of protein synthesis rates (-34%) occurred in the fasted and fed states, whereas a higher protein content (+10%) was observed. In the kidneys, a slight inhibition of synthesis rates after the HP diet was also observed but remained without effect on kidney protein pool size. Stomach and skin protein synthesis rates were significantly increased under HP conditions, whereas protein anabolism in skeletal muscle remained insensitive to the dietary protein level. This was also true for specific muscle protein fractions: myosin, mitochondrial, or sarcoplasmic protein synthesis rates were influenced by neither the dietary protein level nor the nutritional status.
  
  
  CONCLUSIONS
  Modulation of protein kinetics and accretion by the HP diet is tissue-specific and the liver plays a critical role in such adaptations in a unique situation associating an inhibition of protein synthesis and protein pool expansion. The mechanisms underlying these changes and their physiologic incidence remain to be elucidated.
authors.affiliation: INRA, CNRH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Chevalier
authors.forename: Cécile
authors.initials: C
authors.lastname: Bos
authors.forename: Céline
authors.initials: C
authors.lastname: Gryson
authors.forename: Catherine
authors.initials: C
authors.lastname: Luengo
authors.forename: Stéphane
authors.initials: S
authors.lastname: Walrand
authors.forename: Daniel
authors.initials: D
authors.lastname: Tomé
authors.forename: Yves
authors.initials: Y
authors.lastname: Boirie
authors.forename: Claire
authors.initials: C
authors.lastname: Gaudichon
mesh_terms: D000818:Animals; D001835:Body Weight; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000378:metabolism / Q000494:pharmacology; D005753:Gastric Mucosa / Q000378:metabolism; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000187:drug effects / Q000378:metabolism; D013270:Stomach / Q000187:drug effects; D014018:Tissue Distribution
chemical_list: D004044:Dietary Proteins; D011506:Proteins