Genetic strain-dependent protein metabolism and muscle hypertrophy under chronic isometric training in rat gastrocnemius muscle

Genetic strain-dependent reactivity to mechanical stimuli in rat skeletal muscle has not been examined. This study aimed to examine whether genetic strain-dependency is associated with reactivity in protein metabolism and the resultant muscle hypertrophy after isometric resistance training (RT). The...

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Bibliographic Details
Published inPhysiological research Vol. 61; no. 5; pp. 527 - 535
Main Authors Kobayashi, K, Ogasawara, R, Tsutaki, A, Lee, K, Ochi, E, Nakazato, K
Format Journal Article
LanguageEnglish
Published Czech Republic Institute of Physiology 01.01.2012
Subjects
Animals
Enzymes
Hypertrophy - physiopathology
Male
Muscle Proteins - genetics
Muscle Proteins - metabolism
Muscle, Skeletal - pathology
Muscle, Skeletal - physiopathology
Muscular system
Physical Conditioning, Animal - methods
Proteins
Rats
Rats, Sprague-Dawley
Rodents
Species Specificity
Studies
Japan
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Summary:Genetic strain-dependent reactivity to mechanical stimuli in rat skeletal muscle has not been examined. This study aimed to examine whether genetic strain-dependency is associated with reactivity in protein metabolism and the resultant muscle hypertrophy after isometric resistance training (RT). The right triceps of Sprague-Dawley (SD) and Wistar rats underwent 12 sessions of RT. After RT, a transition from the IIb to the IIx myosin heavy-chain isoform was observed in both strains. In SD rats, the lateral gastrocnemius muscle (LG) mass of the trained legs (TRN) was significantly higher than that of the control legs (CON) (7.8 %, P<0.05). Meanwhile, in Wistar rats, the LG mass was unchanged. In SD rats, the levels of 70-kDa ribosomal protein S6 kinase (p70S6k) and forkhead box 3a (FOXO3a) phosphorylation in the TRN were significantly greater than those of the CON (2.2- and 1.9-fold, respectively; P<0.05). The expression of muscle ring finger-1 (MuRF1) and muscle atrophy F-box (MAFbx/atrogin-1) in the TRN were significantly lower than those of the CON (0.6- and 0.7-fold, respectively; P<0.05). However, in Wistar rats, there was no significant difference. These results suggest a genetic strain difference in protein metabolism. This phenomenon may be useful for studying individual differences in response to RT.
ISSN:0862-8408
1802-9973
DOI:10.33549/physiolres.932312