Acute bout of resistance exercise increases vitamin D receptor protein expression in rat skeletal muscle.
What is the central question of this study? Does an acute bout of exercise alter vitamin D receptor expression in rat skeletal muscle? What is the main finding and its importance? Resistance exercise but not endurance exercise increased intramuscular vitamin D receptor expression. Thus, resistance exercise may be an effective way to increase muscle vitamin D receptor expression. Vitamin D and vitamin D receptor (VDR) are involved in the maintenance of skeletal muscle mass and function. Although resistance exercise is well known to enhance muscle growth and improve muscle function, the effect of resistance exercise on VDR has been unclear. We investigated intramuscular VDR expression in response to an acute bout of resistance exercise or endurance exercise. Male adult Sprague-Dawley rats were subjected to either resistance exercise (isometrically exercised via percutaneous electrical stimulation for five sets of ten 3 s contractions, with a 7 s interval between contractions and 3 min rest intervals between sets) or endurance exercise (treadmill at 25 m min(-1) for 60 min). Rats were killed immediately or 1, 3, 6 or 24 h after completion of the resistance or endurance exercise, and gastrocnemius muscles were removed. Non-exercised control animals were killed in a basal state (control group). Intramuscular VDR expression was significantly higher immediately after resistance exercise and elevated for 3 h after exercise compared with the control group (P < 0.05), and the resistance exercise significantly increased phosphorylated ERK1/2 and Mnk1 expression (P < 0.05), which may be associated with VDR expression, immediately after exercise. Additionally, intramuscular expression of cytochrome P450 27B1, an enzyme related to vitamin D metabolism, was significantly higher at 1 and 3 h after exercise (P < 0.05) compared with the control group. In contrast, endurance exercise had no effect on any of the measured proteins. Our results indicate that resistance exercise may be an efficient way to increase intramuscular VDR and related enzyme expression.
Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Kusatsu, Shiga, Japan.
Yuhei
Y
Makanae
Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.
Riki
R
Ogasawara
Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
Koji
K
Sato
Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
Yusuke
Y
Takamura
Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
Kenji
K
Matsutani
Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
Kohei
K
Kido
Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
Naruhiro
N
Shiozawa
Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan.
Koichi
K
Nakazato
Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
Satoshi
S
Fujita
D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000378:metabolism; D000818:Animals; D002112:Calcifediol / Q000097:blood; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism*; D010766:Phosphorylation; D010807:Physical Endurance; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D018167:Receptors, Calcitriol / Q000378:metabolism*; D055070:Resistance Training; D012420:Running; D013997:Time Factors; D015854:Up-Regulation
D018167:Receptors, Calcitriol; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; C491394:Mknk1 protein, rat; D017346:Protein Serine-Threonine Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D002112:Calcifediol