AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 3 770-R776, Copyright © 1990 by American Physiological Society

ARTICLES

Training improves glucose homeostasis in rats during exercise via glucose production

C. M. Donovan and K. D. Sumida
Department of Exercise Science, University of Southern California, Los Angeles 90089-0652.

The effects of endurance training (running 1 h/day at 35 m/min, 10% grade) on glucose homeostasis during exercise (running 20 m/min) was studied in 30-h fasted rats. Primed-continuous infusion of [6-3H]- and [U-14C]glucose were employed to assess rates of appearance (Ra), disappearance (Rd), and apparent recycling. Training resulted in a 65% increase in skeletal muscle succinate dehydrogenase (SDH) activity but did not significantly influence body weight. Resting blood glucose concentrations were not significantly different between controls, 5.01 +/- 0.19 mM, and trained animals, 4.86 +/- 0.16 mM. Exercise resulted in a more rapid decline in blood glucose levels for control animals, reaching a value of 2.35 +/- 0.39 mM at 60 min, compared with 3.69 +/- 0.47 mM for trained animals. Glucose Ra was not significantly different between groups at rest, and rose for both groups during exercise. However, for controls Ra plateaued between 15 and 60 min of exercise at 11.03 +/- 0.73 mumol.100 g-1.min-1, whereas trained animals demonstrated a continuous rise to 17.13 +/- 1.18 mumol.100 g-1.min-1. Glucose Rd values were not significantly different between groups during the first 30 min of exercise but were significantly higher for trained animals during the final 30 min. As a result of the higher glucose Ra, trained animals demonstrated a smaller mean difference between Ra and Rd during exercise when compared with controls, -0.27 +/- 0.14 vs. -0.96 +/- 0.17 mumol.100 g-1.min-1. Trained animals further demonstrated significantly higher rates of glucose carbon recycling during the final 30 min of exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				K. D. Sumida, S. M. Arimoto, M. J. Catanzaro, and F. Frisch Effect of age and endurance training on the capacity for epinephrine-stimulated gluconeogenesis in rat hepatocytes J Appl Physiol, August 1, 2003; 95(2): 712 - 719. [Abstract] [Full Text] [PDF]

				M. J. Roef, K. de Meer, S. C. Kalhan, H. Straver, R. Berger, and D.-J. Reijngoud Gluconeogenesis in humans with induced hyperlactatemia during low-intensity exercise Am J Physiol Endocrinol Metab, June 1, 2003; 284(6): E1162 - E1171. [Abstract] [Full Text] [PDF]

				B. F. Miller, J. A. Fattor, K. A. Jacobs, M. A. Horning, S.-H. Suh, F. Navazio, and G. A. Brooks Metabolic and cardiorespiratory responses to "the lactate clamp" Am J Physiol Endocrinol Metab, November 1, 2002; 283(5): E889 - E898. [Abstract] [Full Text] [PDF]

				D. A. Podolin, B. K. Wills, I. O. Wood, M. Lopez, R. S. Mazzeo, and D. A. Roth Attenuation of age-related declines in glucagon-mediated signal transduction in rat liver by exercise training Am J Physiol Endocrinol Metab, September 1, 2001; 281(3): E516 - E523. [Abstract] [Full Text] [PDF]

				K. D. Sumida and C. M. Donovan Lactate removal is not enhanced in nonstimulated perfused skeletal muscle after endurance training J Appl Physiol, April 1, 2001; 90(4): 1307 - 1313. [Abstract] [Full Text] [PDF]

				B. C. Bergman, M. A. Horning, G. A. Casazza, E. E. Wolfel, G. E. Butterfield, and G. A. Brooks Endurance training increases gluconeogenesis during rest and exercise in men Am J Physiol Endocrinol Metab, February 1, 2000; 278(2): E244 - E251. [Abstract] [Full Text] [PDF]

				Y. Burelle, C. Fillipi, F. Peronnet, and X. Leverve Mechanisms of increased gluconeogenesis from alanine in rat isolated hepatocytes after endurance training Am J Physiol Endocrinol Metab, January 1, 2000; 278(1): E35 - E42. [Abstract] [Full Text] [PDF]

				D. A. Podolin, Y. Wei, and M. J. Pagliassotti Effects of a high-fat diet and voluntary wheel running on gluconeogenesis and lipolysis in rats J Appl Physiol, April 1, 1999; 86(4): 1374 - 1380. [Abstract] [Full Text] [PDF]

				A. L. Friedlander, G. A. Casazza, M. A. Horning, M. J. Huie, and G. A. Brooks Training-induced alterations of glucose flux in men J Appl Physiol, April 1, 1997; 82(4): 1360 - 1369. [Abstract] [Full Text] [PDF]