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Muscle protein synthesis during the early period of resistance training in rat
Author(s) -
Kotani Takaya,
Takegaki Junya,
Noda Masahumi,
Takagi Ryo,
Nakazato Koichi,
Ishii Naokata
Publication year - 2018
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.2018.32.1_supplement.856.27
Subject(s) - sed , isometric exercise , protein biosynthesis , ribosomal protein s6 , endocrinology , acclimatization , stimulation , medicine , pi3k/akt/mtor pathway , chemistry , biology , signal transduction , microbiology and biotechnology , p70 s6 kinase 1 , biochemistry , botany
Increase in muscle protein synthesis (MPS) by resistance exercise (RE) has been thought to be caused by increases in translational efficiency (major regulator: mammalian target of rapamycin (mTOR) signaling pathway) and translational capacity (ribosome content). It has been shown that repeated bouts of RE leads to the attenuation of the activation of mTOR signaling and the increase in ribosome content after a bout of RE (Ogasawara et al. 2013). However, it is unknown whether MPS response to RE is also declined when exercise bout is repeated. Purpose To see if the acclimatization occurs in the response of protein metabolism to exercise during the course of RE , the present study investigated the changes in MPS, mTOR signaling pathway and ribosome content with the increase of RE bout. Method Male Sprague‐Dawley rats were randomly assigned into three groups: Sedentary (SED), resistance‐trained with 1 bout (1B), 3 bouts (3B). RE protocol consisted of 50 repetitions of maximal isometric contraction of the gastrocnemius muscle elicited by direct electric stimulation under anesthesia. A day recovery period was taken between each bout. Muscle samples were collected 6h after the last RE session. Results Amount of puromycin‐labeled peptides was larger in trained groups than in SED, but no significant difference was seen between 1B and 3B. Posphorylation of p70S6K was larger in trained groups than in SED, and significantly larger in 1B than in 3B. By contrast, ribosomal RNA content was larger in trained groups than in SED, and significantly larger in 3B than in 1B. Conclusion MPS after repeated bouts of RE was unchanged from that after a single bout in spite of the attenuated response of mTOR signaling. This may be caused by the compensatory increase in ribosome content with the increase in the exercise bout. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .