Document Detail

Effects of endurance exercise-training on single-fiber contractile properties of insulin-treated streptozotocin-induced diabetic rats.
MedLine Citation:
PMID:  15831797     Owner:  NLM     Status:  MEDLINE    
The purpose of this study was to characterize the contractile properties of individual skinned muscle fibers from insulin-treated streptozotocin-induced diabetic rats after an endurance exercise training program. We hypothesized that single-fiber contractile function would decrease in the diabetic sedentary rats and that endurance exercise would preserve the function. In the study, 28 rats were assigned to either a nondiabetic sedentary, a nondiabetic exercise, a diabetic sedentary, or a diabetic exercise group. Rats in the diabetic groups received subcutaneous intermediate-lasting insulin daily. The exercise-trained rats ran on a treadmill at a moderate intensity for 60 min, five times per week. After 12 wk, the extensor digitorum longus and soleus muscles were dissected. Single-fiber diameter, Ca(2+)-activated peak force, specific tension, activation threshold, and pCa(50) as well as the myosin heavy chain isoform expression (MHC) were determined. We found that in MHC type II fibers from extensor digitorum longus muscle, diameters were significantly smaller from diabetic sedentary rats compared with nondiabetic sedentary rats (P < 0.001). Among the nondiabetic rats, fiber diameters were smaller with exercise (P = 0.038). The absolute force-generating capacity of single fibers was lower in muscles from diabetic rats. There was greater specific tension (force normalized to cross-sectional area) by fibers from the rats that followed an endurance exercise program compared with sedentary. From the results, we conclude that alterations in the properties of contractile proteins are not implicated in the decrease in strength associated with diabetes and that endurance-exercise training does not prevent or increase muscle weakness in diabetic rats.
Otto A Sanchez; LeAnn M Snow; Dawn A Lowe; Robert C Serfass; LaDora V Thompson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2005-04-14
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  99     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2005 Aug 
Date Detail:
Created Date:  2005-07-15     Completed Date:  2005-09-30     Revised Date:  2014-09-05    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  472-8     Citation Subset:  IM    
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MeSH Terms
Adaptation, Physiological / physiology
Cells, Cultured
Diabetes Mellitus, Experimental / chemically induced,  drug therapy*,  physiopathology*
Insulin / therapeutic use*
Isometric Contraction*
Muscle Fibers, Skeletal*
Muscle, Skeletal / physiopathology*
Physical Conditioning, Animal / methods*
Physical Endurance*
Rats, Sprague-Dawley
Stress, Mechanical
Grant Support
F32 AG005815/AG/NIA NIH HHS; F32 AG005815-02/AG/NIA NIH HHS; K01 AG020990/AG/NIA NIH HHS; K01 AG020990-05/AG/NIA NIH HHS; K02 AG021626/AG/NIA NIH HHS; R01 AG017768/AG/NIA NIH HHS
Reg. No./Substance:
0/Insulin; 5W494URQ81/Streptozocin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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