|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Journal of Experimental Biology, Vol 199, Issue 8 1651-1658, Copyright © 1996 by Company of Biologists
JOURNAL ARTICLES |
TJ Roberts, JM Weber, H Hoppeler, ER Weibel and CR Taylor
Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA.
This paper quantifies maximal flows of carbohydrates and lipids through the pathways supplying the mitochondria. Maximal flow rates are the main functional parameter used in testing the principle of symmorphosis, which states that structural capacities are quantitatively matched to functional demand. Only under rate-limiting conditions will all of the structural capacity be used. Dogs and goats were compared to obtain large differences in absolute rates. We exercised the animals for long enough to reach steady-state O2 and CO2 exchange rates at intensities eliciting 40%, 60% and 85% of the maximal rate of oxygen consumption (MO2max). We then calculated rates of fat and carbohydrate oxidation from the ratio of CO2 produced to O2 consumed (the respiratory exchange ratio). The dog's Mo2max was more than twice that of the goat (6517 versus 3026 mumol O2 kg-1 min-1). We found the same pattern of fuel selection as a function of exercise intensity in both species, and it appears to be general to mammals. Maximal rates of fat oxidation were reached at 40% exercise intensity, where 77% of the energy was supplied by fat. As exercise intensity increased, all additional energy was supplied by carbohydrates. We conclude that the partitioning of fuel supply to the fat and carbohydrate pathways follows the same pattern in both dogs and goats.
This article has been cited by other articles:
|
|
 |
|
  A. Philp, A. L. Macdonald, and P. W. Watt Lactate - a signal coordinating cell and systemic function J. Exp. Biol., December 15, 2005; 208(24): 4561 - 4575. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. J. Pierce, S. R. McWilliams, T. P. O'Connor, A. R. Place, and C. G. Guglielmo Effect of dietary fatty acid composition on depot fat and exercise performance in a migrating songbird, the red-eyed vireo J. Exp. Biol., April 1, 2005; 208(7): 1277 - 1285. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Maffeis, M. Zaffanello, M. Pellegrino, C. Banzato, G. Bogoni, E. Viviani, M. Ferrari, and L. Tato Nutrient Oxidation during Moderately Intense Exercise in Obese Prepubertal Boys J. Clin. Endocrinol. Metab., January 1, 2005; 90(1): 231 - 236. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Haman, S. R. Legault, and J.-M. Weber Fuel selection during intense shivering in humans: EMG pattern reflects carbohydrate oxidation J. Physiol., April 1, 2004; 556(1): 305 - 313. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Haman, F. Peronnet, G. P. Kenny, E. Doucet, D. Massicotte, C. Lavoie, and J.-M. Weber Effects of carbohydrate availability on sustained shivering I. Oxidation of plasma glucose, muscle glycogen, and proteins J Appl Physiol, January 1, 2004; 96(1): 32 - 40. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Haman, S. R. Legault, M. Rakobowchuk, M. B. Ducharme, and J.-M. Weber Effects of carbohydrate availability on sustained shivering II. Relating muscle recruitment to fuel selection J Appl Physiol, January 1, 2004; 96(1): 41 - 49. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. L. Fuson, D. F. Cowan, S. B. Kanatous, L. K. Polasek, and R. W. Davis Adaptations to diving hypoxia in the heart, kidneys and splanchnic organs of harbor seals (Phoca vitulina) J. Exp. Biol., November 15, 2003; 206(22): 4139 - 4154. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Haman, F. Peronnet, G. P. Kenny, D. Massicotte, C. Lavoie, C. Scott, and J.-M. Weber Effect of cold exposure on fuel utilization in humans: plasma glucose, muscle glycogen, and lipids J Appl Physiol, July 1, 2002; 93(1): 77 - 84. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. G. Guglielmo, N. H. Haunerland, P. W. Hochachka, and T. D. Williams Seasonal dynamics of flight muscle fatty acid binding protein and catabolic enzymes in a migratory shorebird Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2002; 282(5): R1405 - R1413. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. B. McClelland, P. W. Hochachka, S. P. Reidy, and J.-M. Weber High-altitude acclimation increases the triacylglycerol/fatty acid cycle at rest and during exercise Am J Physiol Endocrinol Metab, September 1, 2001; 281(3): E537 - E544. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T.-S. TSAO, J. LI, K. S. CHANG, A. E. STENBIT, D. GALUSKA, J. E. ANDERSON, J. R. ZIERATH, R. J. MCCARTER, and M. J. CHARRON Metabolic adaptations in skeletal muscle overexpressing GLUT4: effects on muscle and physical activity FASEB J, April 1, 2001; 15(6): 958 - 969. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Geor, K. W. Hinchcliff, and R. A. Sams beta -Adrenergic blockade augments glucose utilization in horses during graded exercise J Appl Physiol, September 1, 2000; 89(3): 1086 - 1098. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. R. Pendergast, J. J. Leddy, and J. T. Venkatraman A Perspective on Fat Intake in Athletes J. Am. Coll. Nutr., June 1, 2000; 19(3): 345 - 350. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. B. McClelland, P. W. Hochachka, and J.-M. Weber Effect of high-altitude acclimation on NEFA turnover and lipid utilization during exercise in rats Am J Physiol Endocrinol Metab, December 1, 1999; 277(6): E1095 - E1102. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. M. A. L. Pelsers, P. J. Butler, C. M. Bishop, and J. F. C. Glatz Fatty acid binding protein in heart and skeletal muscles of the migratory barnacle goose throughout development Am J Physiol Regulatory Integrative Comp Physiol, March 1, 1999; 276(3): R637 - R643. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. C. Bergman and G. A. Brooks Respiratory gas-exchange ratios during graded exercise in fed and fasted trained and untrained men J Appl Physiol, February 1, 1999; 86(2): 479 - 487. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. B. McClelland, P. W. Hochachka, and J.-M. Weber Carbohydrate utilization during exercise after high-altitude acclimation: A new perspective PNAS, August 18, 1998; 95(17): 10288 - 10293. [Abstract] [Full Text] [PDF]
|
|
