title: Chronic resistance training decreases MuRF-1 and Atrogin-1 gene expression but does not modify Akt, GSK-3beta and p70S6K levels in rats.
abstract: Long-term adaptation to resistance training is probably due to the cumulative molecular effects of each exercise session. Therefore, we studied in female Wistar rats the molecular effects of a chronic resistance training regimen (3 months) leading to skeletal muscle hypertrophy in the plantaris muscle. Our results demonstrated that muscle proteolytic genes MuRF-1 and Atrogin-1 were significantly decreased in the exercised group measured 24 h after the last resistance exercise session (41.64 and 61.19%, respectively; P < 0.05). Nonetheless, when measured at the same time point, 4EBP-1, GSK-3beta and eIF2Bepsilon mRNA levels and Akt, GSK-3beta and p70S6K protein levels (regulators of translation initiation) were not modified. Such data suggests that if gene transcription constitutes a control point in the protein synthesis pathway this regulation probably occurs in early adaptation periods or during extreme situations leading to skeletal muscle remodeling. However, proteolytic gene expression is modified even after a prolonged resistance training regimen leading to moderate skeletal muscle hypertrophy.
authors.affiliation: Laboratory of Applied Nutrition and Metabolism, Physical Education and Sport School, University of Sao Paulo, Av. Prof. Mello Moraes, 65, São Paulo, SP, 05508-900, Brazil. neloz@usp.br
authors.forename: Nelo Eidy
authors.initials: NE
authors.lastname: Zanchi
authors.forename: Mário Alves
authors.initials: MA
authors.lastname: de Siqueira Filho
authors.forename: Fabio Santos
authors.initials: FS
authors.lastname: Lira
authors.forename: José Cesar
authors.initials: JC
authors.lastname: Rosa
authors.forename: Alex Shimura
authors.initials: AS
authors.lastname: Yamashita
authors.forename: Carla Roberta
authors.initials: CR
authors.lastname: de Oliveira Carvalho
authors.forename: Marilia
authors.initials: M
authors.lastname: Seelaender
authors.forename: Antonio Herbert
authors.initials: AH
authors.lastname: Lancha
mesh_terms: D000818:Animals; D005260:Female; D015870:Gene Expression; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D009124:Muscle Proteins / Q000187:drug effects / Q000378:metabolism*; D053580:Muscle Strength; D010805:Physical Conditioning, Animal; D010807:Physical Endurance; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D017208:Rats, Wistar; D055070:Resistance Training; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism*; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases / Q000187:drug effects / Q000378:metabolism*
chemical_list: D009124:Muscle Proteins; D000070584:Tripartite Motif Proteins; C499086:Trim63 protein, rat; D044767:Ubiquitin-Protein Ligases; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D051057:Proto-Oncogene Proteins c-akt; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D038362:Glycogen Synthase Kinase 3