| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Intramuscular triacylglycerol is an important energy store and is also related to insulin resistance. The mobilization of fatty acids from this pool is probably regulated by hormone-sensitive lipase (HSL), which has recently been shown to exist in muscle and to be activated by both adrenaline and contractions. Adrenaline acts via cAMP-dependent protein kinase (PKA). The signalling mediating the effect of contractions is unknown and was explored in this study. Incubated soleus muscles from 70 g male rats were electrically stimulated to perform repeated tetanic contractions for 5 min. The contraction-induced activation of HSL was abolished by the protein kinase C (PKC) inhibitors bisindolylmaleimide I and calphostin C and reduced 50 % by the mitogen-activated protein kinase kinase (MEK) inhibitor U0126, which also completely blocked extracellular signal-regulated kinase (ERK) 1 and 2 phosphorylation. None of the inhibitors reduced adrenaline-induced HSL activation in soleus muscle. Both phorbol-12-myristate-13-acetate (PMA), which activates PKC and, in turn, ERK, and caffeine, which increases intracellular Ca2+ without eliciting contraction, increased HSL activity. Activated ERK increased HSL activity in supernatant from basal but not from electrically stimulated muscle. In conclusion, in muscle, PKC can stimulate HSL through ERK. Contractions and adrenaline enhance muscle HSL activity by different signalling mechanisms. The effect of contractions is mediated by PKC, at least partly via the ERK pathway.
This article has been cited by other articles:
|
|
 |
|
  M. A. Raney and L. P. Turcotte Evidence for the involvement of CaMKII and AMPK in Ca2+-dependent signaling pathways regulating FA uptake and oxidation in contracting rodent muscle J Appl Physiol, May 1, 2008; 104(5): 1366 - 1373. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Moro, S. Bajpeyi, and S. R. Smith Determinants of intramyocellular triglyceride turnover: implications for insulin sensitivity Am J Physiol Endocrinol Metab, February 1, 2008; 294(2): E203 - E213. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. F. Kramer and L. J. Goodyear Exercise, MAPK, and NF-{kappa}B signaling in skeletal muscle J Appl Physiol, July 1, 2007; 103(1): 388 - 395. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. De Bock, T. Dresselaers, B. Kiens, E. A. Richter, P. Van Hecke, and P. Hespel Evaluation of intramyocellular lipid breakdown during exercise by biochemical assay, NMR spectroscopy, and Oil Red O staining Am J Physiol Endocrinol Metab, July 1, 2007; 293(1): E428 - E434. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Raney and L. P. Turcotte Regulation of contraction-induced FA uptake and oxidation by AMPK and ERK1/2 is intensity dependent in rodent muscle Am J Physiol Endocrinol Metab, December 1, 2006; 291(6): E1220 - E1227. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Roepstorff, M. Donsmark, M. Thiele, B. Vistisen, G. Stewart, K. Vissing, P. Schjerling, D. G. Hardie, H. Galbo, and B. Kiens Sex differences in hormone-sensitive lipase expression, activity, and phosphorylation in skeletal muscle at rest and during exercise Am J Physiol Endocrinol Metab, November 1, 2006; 291(5): E1106 - E1114. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. L. Talanian, R. J. Tunstall, M. J. Watt, M. Duong, C. G. R. Perry, G. R. Steinberg, B. E. Kemp, G. J. F. Heigenhauser, and L. L. Spriet Adrenergic regulation of HSL serine phosphorylation and activity in human skeletal muscle during the onset of exercise Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2006; 291(4): R1094 - R1099. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. Watt, A. G. Holmes, S. K. Pinnamaneni, A. P. Garnham, G. R. Steinberg, B. E. Kemp, and M. A. Febbraio Regulation of HSL serine phosphorylation in skeletal muscle and adipose tissue Am J Physiol Endocrinol Metab, March 1, 2006; 290(3): E500 - E508. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Kiens Skeletal Muscle Lipid Metabolism in Exercise and Insulin Resistance Physiol Rev, January 1, 2006; 86(1): 205 - 243. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. S. Hutchinson and T. Bengtsson {alpha}1A-Adrenoceptors Activate Glucose Uptake in L6 Muscle Cells through a Phospholipase C-, Phosphatidylinositol-3 Kinase-, and Atypical Protein Kinase C-Dependent Pathway Endocrinology, February 1, 2005; 146(2): 901 - 912. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. J Rose, B. J Michell, B. E Kemp, and M. Hargreaves Effect of exercise on protein kinase C activity and localization in human skeletal muscle J. Physiol., December 15, 2004; 561(3): 861 - 870. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. O'Neill, M. J. Watt, G. J. F. Heigenhauser, and L. L. Spriet Effects of reduced free fatty acid availability on hormone-sensitive lipase activity in human skeletal muscle during aerobic exercise J Appl Physiol, November 1, 2004; 97(5): 1938 - 1945. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Roepstorff, B. Vistisen, M. Donsmark, J. N Nielsen, H. Galbo, K. A Green, D. G. Hardie, J. F. P Wojtaszewski, E. A Richter, and B. Kiens Regulation of hormone-sensitive lipase activity and Ser563 and Ser565 phosphorylation in human skeletal muscle during exercise J. Physiol., October 15, 2004; 560(2): 551 - 562. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. Watt, A. G. Holmes, G. R. Steinberg, J. L. Mesa, B. E. Kemp, and M. A. Febbraio Reduced plasma FFA availability increases net triacylglycerol degradation, but not GPAT or HSL activity, in human skeletal muscle Am J Physiol Endocrinol Metab, July 1, 2004; 287(1): E120 - E127. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
