Glucose transporters and in vivo glucose uptake in skeletal and cardiac muscle: fasting, insulin stimulation and immunoisolation studies of GLUT1 and GLUT4
| Autor: | J. A. Sowden, Peter W Clark, David E. James, Donald J. Chisholm, Edward W. Kraegen, Kenneth J. Rodnick, M. B. Halstead |
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| Rok vydání: | 1993 |
| Předmět: |
Male
medicine.medical_specialty Monosaccharide Transport Proteins Glucose uptake Muscle Proteins Biochemistry Chromatography Affinity Internal medicine medicine Animals Insulin Tissue Distribution RNA Messenger Rats Wistar Molecular Biology Glucose Transporter Type 1 Glucose Transporter Type 4 biology Muscles Myocardium Cardiac muscle Glucose transporter nutritional and metabolic diseases Skeletal muscle Biological Transport Heart Fasting Cell Biology Glucose clamp technique Rats Glucose Endocrinology medicine.anatomical_structure Glucose Clamp Technique biology.protein GLUT1 hormones hormone substitutes and hormone antagonists GLUT4 Research Article |
| Zdroj: | Biochemical Journal. 295:287-293 |
| ISSN: | 1470-8728 0264-6021 |
| DOI: | 10.1042/bj2950287 |
| Popis: | Our aim was to study glucose transporters GLUT1 and GLUT4 in relation to in vivo glucose uptake in rat cardiac and skeletal muscle. The levels of both transporters were of a similar order of magnitude in whole muscle tissue (GLUT1/GLUT4 ratio varied from 0.1 to 0.6), suggesting that both may have an important physiological role in regulating muscle glucose metabolism. GLUT4 correlated very strongly (r2 = 0.97) with maximal insulin-stimulated glucose uptake (Rg' max., estimated using the glucose clamp plus 2-deoxy[3H]glucose bolus technique) in six skeletal muscles and heart. A distinct difference in regulation of the two transporters was evident in heart: in 5 h-fasted rats, basal glucose uptake and GLUT1 levels in heart were very high and both were reduced, by 90 and 60% respectively, by 48 h fasting. However, in heart (and in red skeletal muscle), neither GLUT4 levels nor Rg' max. were reduced by 48 h fasting. GLUT1 was shown to be specifically expressed in cardiac myocytes, because intracellular vesicles enriched in GLUT4 contained significant levels of GLUT1. In conclusion, the high association of muscle GLUT4 content with insulin responsiveness in different muscles, and the preservation of both with fasting, supports a predominant role of GLUT4 in insulin-mediated glucose uptake. GLUT1 may play an important role in mediating cardiac muscle glucose uptake in the basal metabolic state. Marked changes in GLUT1 expression with alterations in the metabolic state, such as prolonged fasting, may play an important role in cardiac glucose metabolism. |
| Databáze: | OpenAIRE |
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