Transgenic mice overexpressing GLUT-1 protein in muscle exhibit increased muscle glycogenesis after exercise
| Autor: | Bess A. Marshall, Nicole Barucci, Polly A. Hansen, Jian-Ming Ren, Gerald I. Shulman, Mike Mueckler |
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| Rok vydání: | 2000 |
| Předmět: |
Blood Glucose
Male Genetically modified mouse medicine.medical_specialty Glycogenolysis Monosaccharide Transport Proteins Antimetabolites Physiology Endocrinology Diabetes and Metabolism Physical Exertion Mice Transgenic Physical exercise Deoxyglucose Fatty Acids Nonesterified Biology Phosphates Mice Gastrocnemius muscle chemistry.chemical_compound Physiology (medical) Internal medicine medicine Animals Humans Insulin Muscle Skeletal Glycogen synthase Swimming Glucose Transporter Type 1 Glycogen Glucose transporter Glycogen Synthase Endocrinology chemistry Glycogenesis biology.protein Lithium Chloride |
| Zdroj: | American Journal of Physiology-Endocrinology and Metabolism. 278:E588-E592 |
| ISSN: | 1522-1555 0193-1849 |
| DOI: | 10.1152/ajpendo.2000.278.4.e588 |
| Popis: | The purpose of the present study was to determine the rates of muscle glycogenolysis and glycogenesis during and after exercise in GLUT-1 transgenic mice and their age-matched littermates. Male transgenic mice (TG) expressing a high level of human GLUT-1 and their nontransgenic (NT) littermates underwent 3 h of swimming. Glycogen concentration was determined in gastrocnemius and extensor digitorum longus (EDL) muscles before exercise and at 0, 5, and 24 h postexercise, during which food (chow) and 10% glucose solution (as drinking water) were provided. Exercise resulted in approximately 90% reduction in muscle glycogen in both NT (from 11.2 +/- 1.4 to 2. 1 +/- 1.3 micromol/g) and TG (from 99.3 +/- 4.7 to 11.8 +/- 4.3 micromol/g) in gastrocnemius muscle. During recovery from exercise, the glycogen concentration increased to 38.2 +/- 7.3 (5 h postexercise) and 40.5 +/- 2.8 micromol/g (24 h postexercise) in NT mice. In TG mice, however, the increase in muscle glycogen concentration during recovery was greater (to 57.5 +/- 7.4 and 152.1 +/- 15.7 micromol/g at 5 and 24 h postexercise, respectively). Similar results were obtained from EDL muscle. The rate of 2-deoxyglucose uptake measured in isolated EDL muscles was 7- to 10-fold higher in TG mice at rest and at 0 and 5 h postexercise. There was no difference in muscle glycogen synthase activation measured in gastrocnemius muscles between NT and TG mice immediately after exercise. These results demonstrate that the rate of muscle glycogen accumulation postexercise exhibits two phases in TG: 1) an early phase (0-5 h), with rapid glycogen accumulation similar to that of NT mice, and 2) a progressive increase in muscle glycogen concentration, which differs from that of NT mice, during the second phase (5-24 h). Our data suggest that the high level of steady-state muscle glycogen in TG mice is due to the increase in muscle glucose transport activity. |
| Databáze: | OpenAIRE |
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