title: Whey protein modifies gene expression related to protein metabolism affecting muscle weight in resistance-exercised rats.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effects of resistance exercise on the mRNA expression of muscle mammalian target of rapamycin (mTOR), muscle-specific RING finger-1 (MuRF-1), and muscle atrophy F-box (MAFbx) in the presence or absence of whey protein ingestion. We hypothesized that resistance exercise in combination with whey protein ingestion alters the gene expression of proteins related to muscle protein synthesis (mTOR) and/or degradation (MuRF-1 and MAFbx), thus affecting muscle weight gain in rats.
  
  
  METHODS
  Thirty-two male Fischer rats were randomly assigned to the following four experimental groups (n = 8/group): Control sedentary, control exercised, whey protein sedentary, and whey protein exercised. Exercise consisted of inducing the animals to perform sets of jumps for 8 wk. Body weight gain, muscle weights, food intake, and feeding efficiency were evaluated. Gene expressions were analyzed by quantitative real-time reverse transcription polymerase chain reaction. Statistical evaluation was performed using a two-way analysis of variance with a Tukey post hoc test.
  
  
  RESULTS
  Whey protein exercised rats exhibited higher body and muscle weight gain compared with control-exercised rats (P = 0.032). The expression of mTOR was reduced by exercise but increased when whey protein was consumed as a dietary protein (P = 0.005). MuRF-1 expression was reduced by exercise (P < 0.001), whereas MAFbx was reduced only by whey protein ingestion (P = 0.008) independent of exercise.
  
  
  CONCLUSIONS
  A reduction in MAFbx gene transcription induced by whey protein and the interaction between exercise and whey protein ingestion on mTOR gene expression contributed significantly to differences in body and muscle weight gain.
authors.affiliation: Research Center in Biological Sciences (NUPEB), Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil; Department of Integrated Health (DEIS), Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil. Electronic address: fabianokenji@gmail.com.
authors.forename: Fabiano Kenji
authors.initials: FK
authors.lastname: Haraguchi
authors.affiliation: Research Center in Biological Sciences (NUPEB), Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil; Department of Biological Sciences (DECBI), Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
authors.forename: Cintia Lopes
authors.initials: CL
authors.lastname: de Brito Magalhães
authors.affiliation: Research Center in Biological Sciences (NUPEB), Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
authors.forename: Leandro Xavier
authors.initials: LX
authors.lastname: Neves
authors.affiliation: Department of Foods, School of Nutrition, Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
authors.forename: Rinaldo Cardoso
authors.initials: RC
authors.lastname: dos Santos
authors.affiliation: Research Center in Biological Sciences (NUPEB), Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil; Department of Biological Sciences (DECBI), Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
authors.forename: Maria Lúcia
authors.initials: ML
authors.lastname: Pedrosa
authors.affiliation: Research Center in Biological Sciences (NUPEB), Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil; Department of Foods, School of Nutrition, Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
authors.forename: Marcelo Eustáquio
authors.initials: ME
authors.lastname: Silva
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004044:Dietary Proteins / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D008297:Male; D008894:Milk Proteins / Q000494:pharmacology*; D009068:Movement; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D010805:Physical Conditioning, Animal; D059385:Plyometric Exercise; D014176:Protein Biosynthesis; D059748:Proteolysis; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D011916:Rats, Inbred F344; D055070:Resistance Training; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D000067816:Whey Proteins
chemical_list: D004044:Dietary Proteins; D008894:Milk Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; D000070584:Tripartite Motif Proteins; D000067816:Whey Proteins; C499086:Trim63 protein, rat; D044767:Ubiquitin-Protein Ligases; C546845:mTOR protein, rat; D058570:TOR Serine-Threonine Kinases
keywords: Dietary protein; Exercise; MAFbx; MuRF-1; Protein degradation; Protein synthesis; mTOR