Document Detail

Effects of life-long exercise on circulating free fatty acids and muscle triglyceride content in ageing rats.
MedLine Citation:
PMID:  15489056     Owner:  NLM     Status:  MEDLINE    
Regular physical exercise has emerged, together with dietary restriction, as an effective intervention in delaying degenerative diseases and augmenting life span in rodents. The mechanisms involved remain largely unknown, although a beneficial influence on the age-related alteration of insulin sensitivity has been hypothesized. As muscle triglyceride (TG) accumulation is considered a reliable index of muscle insulin resistance, in this study we explored muscle TG content in 23-month-old male Sprague-Dawley rats subjected to life-long training. Plasma glucose, insulin, free fatty acid (FFA) and leptin levels were also measured. Both voluntary running in wheels (RW) and forced training in treadmill (TM) were studied. As RW rats weighed less than controls, a cohort of untrained animals, fed to pair weight (PW) with RW, was added to discriminate the effect of exercise from that of food restriction. Sedentary ad libitum fed rats served as controls. In 23-month-old RW rats, muscle TG content was reduced by 50% with respect to age-matched sedentary controls, while in TM group this reduction was smaller but still highly significant, and occurred independently on the changes in body fat mass. In both the trained rat groups, there was a significant decrease in circulating FFA levels and a trend to reduced insulin levels. In PW rats, muscle TG levels decreased similarly to RW rats, while plasma parameters were less modified. In particular, RW training was more effective than PW in preventing the age-related increase in circulating leptin levels. Our results suggest that voluntary exercise effectively counteracts the development of insulin resistance in the muscles of ageing rats as well as other related changes such as hyperlipacidaemia and compensatory hyperleptinaemia. Forced training or moderate food restriction appear slightly less effective than voluntary exercise in preventing age-dependent alterations in nutrient distribution and/or utilization.
Michela Novelli; Alessandro Pocai; Monika Skalicky; Andrus Viidik; Ettore Bergamini; Pellegrino Masiello
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Experimental gerontology     Volume:  39     ISSN:  0531-5565     ISO Abbreviation:  Exp. Gerontol.     Publication Date:  2004 Sep 
Date Detail:
Created Date:  2004-10-18     Completed Date:  2005-02-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0047061     Medline TA:  Exp Gerontol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1333-40     Citation Subset:  IM    
Copyright Information:
Copyright 2004 Elsevier Inc.
Dipartimento di Patologia Sperimentale, B.M.I.E., University of Pisa, Via Roma, 55-Scuola Medica, Pisa I-56126, Italy.
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MeSH Terms
Adipose Tissue / anatomy & histology
Aging / metabolism*
Blood Glucose / metabolism
Body Weight / physiology
Fatty Acids, Nonesterified / blood*
Insulin / blood
Leptin / blood
Motor Activity / physiology*
Muscle, Skeletal / metabolism*
Rats, Sprague-Dawley
Triglycerides / metabolism*
Reg. No./Substance:
0/Blood Glucose; 0/Fatty Acids, Nonesterified; 0/Leptin; 0/Triglycerides; 11061-68-0/Insulin

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