Adipose triglyceride lipase in human skeletal muscle is upregulated by exercise training
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Mobilization of fatty acids from stored triacylglycerol (TG) in adipose tissue and skeletal muscle [intramyocellular triacylglycerol (IMTG)] requires activity of lipases. Although exercise training increases the lipolytic capacity of skeletal muscle, the expression of hormone-sensitive lipase (HSL) is not changed. Recently, adipose triglyceride lipase (ATGL) was identified as a TG-specific lipase in various rodent tissues. To investigate whether human skeletal muscle ATGL protein is regulated by endurance exercise training, 10 healthy young men completed 8 wk of supervised endurance exercise training. Western blotting analysis on lysates of skeletal muscle biopsy samples revealed that exercise training induced a twofold increase in skeletal muscle ATGL protein content. In contrast to ATGL, expression of comparative gene identification 58 (CGI-58), the activating protein of ATGL, and HSL protein was not significantly changed after the training period. The IMTG concentration was significantly decreased by 28% at termination of the training program compared with before. HSL-phoshorylation at Ser(660) was increased, HSL-Ser(659) phosporylation was unchanged, and HSL-phoshorylation at Ser(565) was decreased altogether, indicating an enhanced basal activity of this lipase. No change was found in the expression of diacylglycerol acyl transferase 1 (DGAT1) after training. Inhibition of HSL with a monospecific, small molecule inhibitor (76-0079) and stimulation of ATGL with CGI-58 revealed that significant ATGL activity is present in human skeletal muscle. These results suggest that ATGL in addition to HSL may be important for human skeletal muscle lipolysis.
Originalsprog | Engelsk |
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Tidsskrift | American Journal of Physiology: Endocrinology and Metabolism |
Vol/bind | 296 |
Udgave nummer | 3 |
Sider (fra-til) | E445-E453 |
Antal sider | 9 |
ISSN | 0193-1849 |
DOI | |
Status | Udgivet - 2009 |
Bibliografisk note
CURIS 2009 5200 014
ID: 11638958