| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Medicine, McMaster University, Hamilton, Ontario L8N 3Z5; and 2 Department of Human Biology and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1
The time course for the activation of glycogen phosphorylase (Phos) and pyruvate dehydrogenase (PDH) and their allosteric regulators was determined in human skeletal muscle during repeated bouts of maximal exercise. Six subjects completed three 30-s bouts of maximal isokinetic cycling separated by 4-min recovery periods. Muscle biopsies were taken at rest and at 6, 15, and 30 s of exercise during bouts 1 and 3. Phos was rapidly activated within the first 6 s of bout 1 from 12% at rest to 47% at 6 s. The activation of PDH increased from 14% at rest to 48% at 6 s and 95% at 15 s of bout 1. Phos reverted back to basal values at the end of the first bout, whereas PDH remained fully activated. In contrast, in the third bout, PDH was 42% at rest and was activated more rapidly and was nearly completely activated by 6 s, whereas Phos remained at basal levels (range 14-20%). Lactate accumulation was marked in the first bout and increased progressively from 2.7 to 76.1 mmol/kg dry wt with no further increase in bout 3. Glycogen utilization was also marked in the first bout and was negligible in bout 3. The rapid activation of Phos and slower activation of PDH in bout 1 was probably due to Ca2+ release from the sarcoplasmic reticulum. Lactate accumulation appeared to be due to an imbalance of the relative activities of Phos and PDH. The increase in H+ concentration may have served to reduce pyruvate production by inhibiting Phos transformation and may have simultaneously activated PDH in the third bout such that there was a better matching between pyruvate production and oxidation and minimal lactate accumulation. As each bout progressed and with successive bouts, there was a decreasing ability to stimulate substrate phosphorylation through phosphocreatine hydrolysis and glycolysis and a shift toward greater reliance on oxidative phosphorylation.
pyruvate dehydrogenase; lactate metabolism; acetylcarnitine; glycolysis; oxidative phosphorylation; phosphocreatine
This article has been cited by other articles:
|
|
 |
|
  K. A. Burgomaster, N. M. Cermak, S. M. Phillips, C. R. Benton, A. Bonen, and M. J. Gibala Divergent response of metabolite transport proteins in human skeletal muscle after sprint interval training and detraining Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2007; 292(5): R1970 - R1976. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. J. Gurd, S. J. Peters, G. J. F. Heigenhauser, P. J. LeBlanc, T. J. Doherty, D. H. Paterson, and J. M. Kowalchuk Prior heavy exercise elevates pyruvate dehydrogenase activity and speeds O2 uptake kinetics during subsequent moderate-intensity exercise in healthy young adults J. Physiol., December 15, 2006; 577(3): 985 - 996. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. A. Burgomaster, G. J. F. Heigenhauser, and M. J. Gibala Effect of short-term sprint interval training on human skeletal muscle carbohydrate metabolism during exercise and time-trial performance J Appl Physiol, June 1, 2006; 100(6): 2041 - 2047. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. R. Gray, G. De Vito, M. A. Nimmo, D. Farina, and R. A. Ferguson Skeletal muscle ATP turnover and muscle fiber conduction velocity are elevated at higher muscle temperatures during maximal power output development in humans Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2006; 290(2): R376 - R382. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. A. Burgomaster, S. C. Hughes, G. J. F. Heigenhauser, S. N. Bradwell, and M. J. Gibala Six sessions of sprint interval training increases muscle oxidative potential and cycle endurance capacity in humans J Appl Physiol, June 1, 2005; 98(6): 1985 - 1990. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. J. Gurd, B. W. Scheuermann, D. H. Paterson, and J. M. Kowalchuk Prior heavy-intensity exercise speeds V{middle dot}O2 kinetics during moderate-intensity exercise in young adults J Appl Physiol, April 1, 2005; 98(4): 1371 - 1378. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. A. Roberts, S. J. G. Loxham, S. M. Poucher, D. Constantin-Teodosiu, and P. L. Greenhaff Acetyl-CoA provision and the acetyl group deficit at the onset of contraction in ischemic canine skeletal muscle Am J Physiol Endocrinol Metab, February 1, 2005; 288(2): E327 - E334. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. L. Calbet, J. A. De Paz, N. Garatachea, S. Cabeza de Vaca, and J. Chavarren Anaerobic energy provision does not limit Wingate exercise performance in endurance-trained cyclists J Appl Physiol, February 1, 2003; 94(2): 668 - 676. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. G. Richards, G. J. F. Heigenhauser, and C. M. Wood Lipid oxidation fuels recovery from exhaustive exercise in white muscle of rainbow trout Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2002; 282(1): R89 - R99. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Bangsbo, M. J. Gibala, P. Krustrup, J. Gonzalez-Alonso, and B. Saltin Enhanced pyruvate dehydrogenase activity does not affect muscle O2 uptake at onset of intense exercise in humans Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2002; 282(1): R273 - R280. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. U. Saunders, M. J. Watt, A. P. Garnham, L. L. Spriet, M. Hargreaves, and M. A. Febbraio No effect of mild heat stress on the regulation of carbohydrate metabolism at the onset of exercise J Appl Physiol, November 1, 2001; 91(5): 2282 - 2288. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Shearer, I. Marchand, M. A. Tarnopolsky, D. J. Dyck, and T. E. Graham Pro- and macroglycogenolysis during repeated exercise: roles of glycogen content and phosphorylase activation J Appl Physiol, March 1, 2001; 90(3): 880 - 888. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. L. Parolin, L. L. Spriet, E. Hultman, M. P. Matsos, M. G. Hollidge-Horvat, N. L. Jones, and G. J. F. Heigenhauser Effects of PDH activation by dichloroacetate in human skeletal muscle during exercise in hypoxia Am J Physiol Endocrinol Metab, October 1, 2000; 279(4): E752 - E761. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. L. Parolin, L. L. Spriet, E. Hultman, M. G. Hollidge-Horvat, N. L. Jones, and G. J. F. Heigenhauser Regulation of glycogen phosphorylase and PDH during exercise in human skeletal muscle during hypoxia Am J Physiol Endocrinol Metab, March 1, 2000; 278(3): E522 - E534. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Howlett, G. J. F. Heigenhauser, and L. L. Spriet Skeletal muscle metabolism during high-intensity sprint exercise is unaffected by dichloroacetate or acetate infusion J Appl Physiol, November 1, 1999; 87(5): 1747 - 1751. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. J. Stephens, Z.-P. Chen, B. J. Canny, B. J. Michell, B. E. Kemp, and G. K. McConell Progressive increase in human skeletal muscle AMPKalpha 2 activity and ACC phosphorylation during exercise Am J Physiol Endocrinol Metab, March 1, 2002; 282(3): E688 - E694. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. G. Richards, G. J. F. Heigenhauser, and C. M. Wood Glycogen phosphorylase and pyruvate dehydrogenase transformation in white muscle of trout during high-intensity exercise Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2002; 282(3): R828 - R836. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
