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

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

  • Thomas J Alsted
  • Martina Schweiger
  • Nybo, Lars
  • Christian Fledelius
  • Poul Jacobsen
  • Robert Zimmermann
  • Rudolf Zechner
  • Kiens, Bente
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.
OriginalsprogEngelsk
TidsskriftAmerican Journal of Physiology: Endocrinology and Metabolism
Vol/bind296
Udgave nummer3
Sider (fra-til)E445-E453
Antal sider9
ISSN0193-1849
DOI
StatusUdgivet - 2009

Bibliografisk note

CURIS 2009 5200 014

ID: 11638958