TY - JOUR
T1 - Exercise training, glucose transporters, and glucose transport in rat skeletal muscles
AU - Rodnick, K. J.
AU - Henriksen, E. J.
AU - James, D. E.
AU - Holloszy, J. O.
PY - 1992
Y1 - 1992
N2 - It was previously found that voluntary wheel running induces an increase in the insulin-sensitive glucose transporter, i.e., the GLUT4 isoform, in rat plantaris muscle (K.J. Rodnick, J.O. Holloszy, C.E. Mondon, and D.E. James. Diabetes 39: 1425-1429, 1990). The present study was undertaken to determine whether 1) the increase in muscle GLUT4 protein is associated with an increase in maximally stimulated glucose transport activity, 2) a conversion of type IIb to type IIa or type I muscle fibers plays a role in the increase in GLUT4 protein, and 3) an increase in the GLUT1 isoform is a component of the adaptation of muscle to endurance exercise. Five weeks of voluntary wheel running that resulted in a 33% increase in citrate synthase activity induced a 50% increase in GLUT4 protein in epitrochlearis muscles of female Sprague-Dawley rats. The rate of 2-deoxyglucose transport maximally stimulated with insulin or insulin plus contractions was increased ~40% (P < 0.05). There was no change in muscle fiber type composition, evaluated by myosin ATPase staining, in the epitrochlearis. There was also no change in GLUT1 protein concentration. We conclude that an increase in GLUT4, but not of GLUT1 protein, is a component of the adaptive response of muscle to endurance exercise and that the increase in GLUT4 protein is associated with an increased capacity for glucose transport.
AB - It was previously found that voluntary wheel running induces an increase in the insulin-sensitive glucose transporter, i.e., the GLUT4 isoform, in rat plantaris muscle (K.J. Rodnick, J.O. Holloszy, C.E. Mondon, and D.E. James. Diabetes 39: 1425-1429, 1990). The present study was undertaken to determine whether 1) the increase in muscle GLUT4 protein is associated with an increase in maximally stimulated glucose transport activity, 2) a conversion of type IIb to type IIa or type I muscle fibers plays a role in the increase in GLUT4 protein, and 3) an increase in the GLUT1 isoform is a component of the adaptation of muscle to endurance exercise. Five weeks of voluntary wheel running that resulted in a 33% increase in citrate synthase activity induced a 50% increase in GLUT4 protein in epitrochlearis muscles of female Sprague-Dawley rats. The rate of 2-deoxyglucose transport maximally stimulated with insulin or insulin plus contractions was increased ~40% (P < 0.05). There was no change in muscle fiber type composition, evaluated by myosin ATPase staining, in the epitrochlearis. There was also no change in GLUT1 protein concentration. We conclude that an increase in GLUT4, but not of GLUT1 protein, is a component of the adaptive response of muscle to endurance exercise and that the increase in GLUT4 protein is associated with an increased capacity for glucose transport.
KW - Epitrochlearis
KW - GLUT4
KW - Soleus
KW - Voluntary wheel running
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U2 - 10.1152/ajpcell.1992.262.1.c9
DO - 10.1152/ajpcell.1992.262.1.c9
M3 - Article
C2 - 1733237
AN - SCOPUS:0026588689
SN - 0002-9513
VL - 262
SP - C9-C14
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
IS - 1 31-1
ER -