Insulin stimulation of muscle protein synthesis in obese Zucker rats is not via a rapamycin-sensitive pathway
| Autor: | James D. Fluckey, G. Lynis Dohm, Todd A. Trappe, Steven C. Pohnert, S. Greg Boyd, Ronald N. Cortright |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
medicine.medical_specialty
Physiology Endocrinology Diabetes and Metabolism medicine.medical_treatment Muscle Proteins Stimulation Biology Insulin resistance Reference Values Physiology (medical) Internal medicine medicine Protein biosynthesis Animals Insulin Obesity Pancreatic hormone Protein Synthesis Inhibitors Sirolimus Ribosomal Protein S6 Kinases Translation (biology) medicine.disease Rats Rats Zucker Drug Combinations Endocrinology Signal transduction Signal Transduction medicine.drug |
| Zdroj: | American Journal of Physiology-Endocrinology and Metabolism. 279:E182-E187 |
| ISSN: | 1522-1555 0193-1849 |
| Popis: | The obese Zucker rat is resistant to insulin for glucose disposal, but it is unknown whether this insulin resistance is accompanied by alterations of insulin-mediated muscle protein synthesis. We examined rates of muscle protein synthesis either with or without insulin in lean and obese Zucker rats with the use of a bilateral hindlimb preparation. Additional experiments examined insulin's effect on protein synthesis with or without rapamycin, an inhibitor of protein synthesis. Protein synthesis in red and white gastrocnemius was stimulated by insulin compared with control (no insulin) in obese ( n = 10, P < 0.05) but not in lean ( n = 10, P > 0.05) Zucker rats. In white gastrocnemius, rapamycin significantly reduced rates of protein synthesis compared with control in lean ( n = 6) and obese ( n = 6) rats; however, in red gastrocnemius, the attenuating effect of rapamycin occurred only in obese rats. The addition of insulin to rapamycin resulted in rates of synthesis that were similar to those for rapamycin alone for lean rats and to those for insulin alone (augmented) for obese rats in both tissues. Our results demonstrate that insulin enhances protein synthesis in muscle that is otherwise characterized as insulin resistant. Furthermore, rapamycin inhibits protein synthesis in muscle of obese Zucker rats; however, stimulation of protein synthesis by insulin is not via a rapamycin-sensitive pathway. |
| Databáze: | OpenAIRE |
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