Postexercise muscle triacylglycerol and glycogen metabolism in obese insulin-resistant Zucker rats

Bruce, C, Hawley, J, Lee, J and Pedersen, B 2004, 'Postexercise muscle triacylglycerol and glycogen metabolism in obese insulin-resistant Zucker rats', Obesity, vol. 12, no. 7, pp. 1158-1165.


Document type: Journal Article
Collection: Journal Articles

Title Postexercise muscle triacylglycerol and glycogen metabolism in obese insulin-resistant Zucker rats
Author(s) Bruce, C
Hawley, J
Lee, J
Pedersen, B
Year 2004
Journal name Obesity
Volume number 12
Issue number 7
Start page 1158
End page 1165
Total pages 8
Publisher North American Association for the Study of Obesity
Abstract OBJECTIVE - To determine the impact of insulin resistance and obesity on muscle triacylglycerol (IMTG) and glycogen metabolism during and after prolonged exercise. RESEARCH METHODS & PROCEDURES - Female lean (fal?; N 40, ZL) and obese insulin-resistant (falfa; N = 40, ZO) Zucker rats performed an acute bout of swimming exercise (8 times for 30 minutes) followed by 6 hours of carbohydrate supplementation (CHO) or fasting (FAST). IMTG and glycogen were measured in the extensor digitorum longus (EDL) and red vastus lateralis (RVL) muscles. RESULTS - Despite resting IMTG content being 4-fold higher in ZO compared with ZL rats, IMTG levels were unchanged in either EDL or RVL muscles immediately after exercise. Resting glycogen concentration in EDL and RVL muscles was similar between genotypes, with exercise resulting in glycogen use in both muscles from ZL rats (-85%, p < 0.05). However, in ZO rats, there was a much smaller decrease in postexercise glycogen content in both EDL and RVL muscles (similar to30%). During postexercise recovery, there was a decrease in EDL muscle levels of IMTG in ZL rats supplemented with CHO after 30 and 360 minutes (p < 0.05). In contrast, IMTG content was increased above resting levels in RVL muscles of ZO rats fasted for 360 minutes. Six hours of CHO refeeding restored glycogen content to resting levels in both muscles in ZL rats. However, after 6 hours of FAST in ZO animals, RVL muscle glycogen content was still lower than resting levels (p < 0.05). At this time, IMTG levels were elevated above basal (p < 0.05). DISCUSSION - In both healthy and insulin-resistant skeletal muscle, there was negligible net IMTG degradation after a single bout of prolonged exercise. However, during postexercise recovery, there was differential metabolism of IMTG between phenotypes.
Subject Cell Metabolism
Keyword(s) Skeletal muscle lipids
insulin resistance
DOI - identifier 10.1038/oby.2004.145
Copyright notice Copyright © 2004 NAASO
ISSN 1071-7323
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