Adipose triglyceride lipase in human skeletal muscle is upregulated by exercise training

作者：Alsted Thomas J; Nybo Lars; Schweiger Martina; Fledelius Christian; Jacobsen Poul; Zimmermann Robert; Zechner Rudolf; Kiens Bente^*

来源：American Journal of Physiology - Endocrinology And Metabolism, 2009, 296(3): E445-E453.

DOI：10.1152/ajpendo.90912.2008

• comparative gene identification 58
• hormone sensitive lipase
• diacylglycerol acyl transferase 1
• intramyocellular triacylglycerol
• lipolysis

Alsted TJ, Nybo L, Schweiger M, Fledelius C, Jacobsen P, Zimmermann R, Zechner R, Kiens B. Adipose triglyceride lipase in human skeletal muscle is upregulated by exercise training. Am J Physiol Endocrinol Metab 296: E445-E453, 2009. First published December 23, 2008; doi:10.1152/ajpendo.90912.2008.-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.

• 出版日期2009-3