Passive stretching produces Akt- and MAPK-dependent augmentations of GLUT4 translocation and glucose uptake in skeletal muscles of mice.
Muscle contraction is accompanied by passive stretching or deformation of cells and tissues. The present study aims to clarify whether or not acute passive stretching evokes glucose transporter 4 (GLUT4) translocation and glucose uptake in skeletal muscles of mice. Passive stretching mainly induced GLUT4 translocation from an intracellular membrane-rich fraction (PF5) to a plasma membrane-rich fraction (F2) and accelerated glucose uptake in hindlimb muscles; whereas electrical stimulation, which mimics physical exercise in vivo, and insulin, each induced GLUT4 translocation from an intracellular membrane-rich fraction (PF5) to a fraction rich in plasma membrane (F2), and to one rich in transverse tubules (PF3), along with subsequent glucose uptake. Mechanical stretching increased phosphorylation of Akt and p38 mitogen-activated protein kinase (p38 MAPK), but it had no apparent effect on the activity of AMP-activated protein kinase (AMPK). Electrical stimulation augmented the activity of not only AMPK but also phosphorylation of Akt and p38 MAPK. Our results suggest that passive stretching produces translocation of GLUT4 mainly from the fraction rich in intracellular membrane to that rich in plasma membrane, and that the glucose uptake could be Akt- and p38 MAPK-dependent, but AMPK-independent manners.
Ito
Yoshihiko
Y
Department of Cellular and Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka City, Shizuoka 422-8526, Japan.
Obara
Kazuo
K
Ikeda
Rikuko
R
Ishii
Megumi
M
Tanabe
Yoshiyuki
Y
Ishikawa
Tomohisa
T
Nakayama
Koichi
K
D000818:Animals; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D009119:Muscle Contraction / Q000502:physiology; D052580:Muscle Stretching Exercises; D018482:Muscle, Skeletal / Q000502:physiology*; D051058:Oncogene Protein v-akt / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology*
D051275:Glucose Transporter Type 4; C495693:Slc2a4 protein, mouse; D051058:Oncogene Protein v-akt; D020929:Mitogen-Activated Protein Kinase Kinases; D005947:Glucose