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Inactivity Suppresses the Expression of Amino Acid Transporters in Rat Skeletal Muscle
Author(s) -
Murakami Taro,
Ishiguro Nahoko,
Yoshinaga Mariko
Publication year - 2013
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.27.1_supplement.713.5
Subject(s) - leucine , skeletal muscle , endocrinology , medicine , muscle hypertrophy , soleus muscle , chemistry , transporter , amino acid , protein biosynthesis , biochemistry , biology , gene
Leucine is one of the building blocks of protein but also stimulates the translation in protein synthesis through the activation of mTORC1 signaling. Furthermore, leucine is oxidized as a fuel to synthesize ATP during exercise in the muscle. These features of leucine let us hypothesized that the expression of leucine transporters would be modified in proportion to its cellular demand induced by physical activity. This study investigated whether the expression of leucine transporters would be induced by voluntary running and reduced by inactivity following the exercise in rat skeletal muscle. Thirty male Fisher 344 × Brown Norway F1 hybrid rats were obtained at 21 days of age. Rats were separated into those with access to running wheels (n=15, wheel lock, WL) and those without access to the wheels (n=15, SED). Forty days after the beginning, wheels were locked at 06:00 and rats were killed 5, 53 or 173 h after locking of wheels. LAT1, CD98, SNAT2, and PAT1 mRNAs in soleus, gastrocnemius, and EDL muscles were measured by qRT‐PCR. Soleus muscle weight was increased by voluntary running and reduced by inactivity following voluntary running. The expression of mRNAs for LAT1 and PAT1 was also induced by voluntary running and reduced by inactivity following it. These results suggested the expression of leucine transporters would be involved in a muscle hypertrophy and atrophy induced by physical activity and inactivity, respectively.