| Muscle fiber type-specific response of Hsp70 expression in human quadriceps following acute isometric exercise. | |
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MedLine Citation:
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PMID: 17916670 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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To investigate the time course of fiber type-specific heat shock protein 70 (Hsp70) expression in human skeletal muscle after acute exercise, 10 untrained male volunteers performed single-legged isometric knee extensor exercise at 60% of their maximal voluntary contraction (MVC) with a 50% duty cycle (5-s contraction and 5-s relaxation) for 30 min. Muscle biopsies were collected from the vastus lateralis before (Pre) exercise in the rested control leg (C) and immediately after exercise (Post) in the exercised leg (E) only and on recovery days 1 (R1), 2 (R2), 3 (R3), and 6 (R6) from both legs. As demonstrated by Western blot analysis, whole muscle Hsp70 content was unchanged (P > 0.05) immediately after exercise (Pre vs. Post), was increased (P < 0.05) by approximately 43% at R1, and remained elevated throughout the entire recovery period in E only. Hsp70 expression was also assessed in individual muscle fiber types I, IIA, and IIAX/IIX by immunohistochemistry. There were no fiber type differences (P > 0.05) in basal Hsp70 expression. Immediately after exercise, Hsp70 expression was increased (P < 0.05) in type I fibers by approximately 87% but was unchanged (P > 0.05) in type II fibers (Pre vs. Post). At R1 and throughout recovery, Hsp70 content in E was increased above basal levels (P < 0.05) in all fiber types, but Hsp70 expression was always highest (P < 0.05) in type I fibers. Hsp70 content in C was not different from Pre at any time throughout recovery. Glycogen depletion was observed at Post in all type II, but not type I, fibers, suggesting that the fiber type differences in exercise-induced Hsp70 expression were not related to glycogen availability. These results demonstrate that the time course of exercise-induced Hsp70 expression in human skeletal muscle is fiber type specific. |
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Authors:
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A R Tupling; E Bombardier; R D Stewart; C Vigna; A E Aqui |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2007-10-04 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 103 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2007 Dec |
Date Detail:
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Created Date: 2007-12-06 Completed Date: 2008-02-21 Revised Date: 2009-11-19 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 2105-11 Citation Subset: IM |
Affiliation:
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Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada. rtupling@uwaterloo.ca |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adolescent Adult Blotting, Western Exercise / physiology* Glycogen / metabolism HSP70 Heat-Shock Proteins / metabolism* Humans Immunohistochemistry Isometric Contraction* Male Muscle Fibers, Fast-Twitch / enzymology, metabolism* Muscle Fibers, Slow-Twitch / enzymology, metabolism* Muscle Strength Myosins / metabolism Quadriceps Muscle / enzymology, metabolism* Reference Values Time Factors Up-Regulation |
| Chemical | |
Reg. No./Substance:
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0/HSP70 Heat-Shock Proteins; 9005-79-2/Glycogen; EC 3.6.4.1/Myosins |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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