Expression of GLUT-4 glucose transporter in unweighted soleus muscle of normal and STZ-induced diabetic rats.
Effects of 6 days of hindlimb suspension on expression of glucose transporters were studied in the skeletal muscle of nondiabetic and streptozotocin-induced diabetic rats. Although total membrane protein recovered from soleus muscles tended to decrease with suspension, GLUT-4 protein concentration (amount per gram membrane protein) was increased by 66 and 91% compared with weight-bearing control in nondiabetic and diabetic rats, respectively. Therefore, the amount of GLUT-4 protein in whole soleus muscle did not decrease with the hindlimb suspension in normal and diabetic rats. In contrast, hindlimb suspension decreased GLUT-4 mRNA amount in whole soleus muscle by 47 and 27% in nondiabetic and diabetic rats, respectively. Thus the GLUT-4 protein-to-GLUT-4 mRNA ratio was increased 2.1-fold in nondiabetic and 1.4-fold in diabetic rats. The extensor digitorum longus muscle, which generally shows little response to unweighting, exhibited no such changes. These results suggest that the amount of GLUT-4 glucose transporter in the unweighted soleus muscle was maintained via a translational and/or posttranslational mechanism in nondiabetic rats as well as in streptozotocin-induced diabetic rats under the condition of reduced weight-bearing activity.
Ishihara
H
H
Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Asano
T
T
Katagiri
H
H
Lin
J L
JL
Tsukuda
K
K
Inukai
K
K
Yazaki
Y
Y
Oka
Y
Y
D000818:Animals; D015152:Blotting, Northern; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000503:physiopathology; D051275:Glucose Transporter Type 4; D006614:Hindlimb / Q000503:physiopathology*; D015151:Immunoblotting; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009043:Motor Activity / Q000502:physiology*; D009124:Muscle Proteins; D009132:Muscles / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values
D051275:Glucose Transporter Type 4; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; C495694:Slc2a4 protein, rat