Insulin-facilitated increase of muscle protein synthesis after resistance exercise involves a MAP kinase pathway
| Autor: | Charlotte A. Peterson, James D. Fluckey, Micheal Knox, Dana Gaddy, Esther E. Dupont-Versteegden, Latasha Smith, Per A. Tesch |
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| Rok vydání: | 2006 |
| Předmět: |
MAPK/ERK pathway
Male medicine.medical_specialty Physiology Endocrinology Diabetes and Metabolism medicine.medical_treatment Physical Exertion Muscle Proteins Biology In Vitro Techniques Muscle hypertrophy Rats Sprague-Dawley Physiology (medical) Internal medicine medicine Primary component Animals Insulin Muscle Skeletal Muscle protein Flavonoids Sirolimus Resistance training Rats Sprague dawley Eukaryotic Initiation Factor-2B Endocrinology Protein Biosynthesis Signal transduction Mitogen-Activated Protein Kinases Signal Transduction |
| Zdroj: | American journal of physiology. Endocrinology and metabolism. 290(6) |
| ISSN: | 0193-1849 |
| Popis: | Recent studies have implicated the mTOR-signaling pathway as a primary component for muscle growth in mammals. The purpose of this investigation was to examine signaling pathways for muscle protein synthesis after resistance exercise. Sprague-Dawley rats (male, 6 mo old) were assigned to either resistance exercise or control groups. Resistance exercise was accomplished in operantly conditioned animals using a specially designed flywheel apparatus. Rats performed two sessions of resistance exercise, separated by 48 h, each consisting of 2 sets of 25 repetitions. Sixteen hours after the second session, animals were killed, and soleus muscles were examined for rates of protein synthesis with and without insulin and/or rapamycin (mTOR inhibitor) and/or PD-098059 (PD; MEK kinase inhibitor). Results of this study demonstrated that rates of synthesis were higher ( P < 0.05) with insulin after exercise compared with without insulin, or to control muscles, regardless of insulin. Rapamycin lowered ( P < 0.05) rates of synthesis in controls, with or without insulin, and after exercise without insulin. However, insulin was able to overcome the inhibition of rapamycin after exercise ( P < 0.05). PD had no effect on protein synthesis in control rats, but the addition of PD to exercised muscle resulted in lower ( P < 0.05) rates of synthesis, and this inhibition was not rescued by insulin. Western blot analyses demonstrated that the inhibitors used in the present study were selective and effective for preventing activation of specific signaling proteins. Together, these results suggest that the insulin-facilitated increase of muscle protein synthesis after resistance exercise requires multiple signaling pathways. |
| Databáze: | OpenAIRE |
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