AJP - Endocrinology and Metabolism, Vol 258, Issue 2 E249-E255, Copyright © 1990 by American Physiological Society

ARTICLES

Amino acid metabolism after intense exercise

J. T. Devlin, I. Brodsky, A. Scrimgeour, S. Fuller and D. M. Bier
Metabolic Unit, University of Vermont College of Medicine, Burlington 05405.

We studied postexercise amino acid metabolism, in the whole body and across the forearm. Seven volunteers were infused with L-[alpha-15N]lysine and L-[1-13C]-leucine twice [one time during 3 h after cycle exercise (75% VO2max), and one time in the resting state]. Whole body protein breakdown was estimated from dilution of L-[alpha-15N]lysine and L-[1-13C]ketoisocaproic acid (KIC) enrichments in plasma. Leucine oxidation was calculated from 13CO2 enrichments in expired air. Whole body protein breakdown was not increased above resting levels during the recovery period. Leucine oxidation was decreased after exercise (postexercise 13 +/- 2.3 vs. resting 19 +/- 3.2 mumol.kg-1.h-1; P less than 0.02), while nonoxidative leucine disposal was increased (115 +/- 6.1 vs. 103 +/- 5.6 micrograms.kg-1.min-1; P less than 0.02). After exercise, forearm net lysine balance was unchanged (87 +/- 25 vs. 93 +/- 28 nmol.100 ml-1.min-1), but there were decreases in forearm muscle protein degradation (219 +/- 51 vs. 356 +/- 85 nmol.100 ml-1.min-1; P less than 0.05) and synthesis (132 +/- 41 vs. 255 +/- 69 nmol.100 ml-1.min-1; P less than 0.01). In conclusion, after exercise 1) whole body protein degradation is not increased, 2) leucine disposal is directed away from oxidative and toward nonoxidative pathways, 3) forearm protein synthesis is decreased. Postexercise increases in whole body protein synthesis occur in tissues other than nonexercised muscle.

This article has been cited by other articles:

				H. Richard-Bulteau, B. Serrurier, B. Crassous, S. Banzet, A. Peinnequin, X. Bigard, and N. Koulmann Recovery of skeletal muscle mass after extensive injury: positive effects of increased contractile activity Am J Physiol Cell Physiol, February 1, 2008; 294(2): C467 - C476. [Abstract] [Full Text] [PDF]

				G. C. Henderson, J. A. Fattor, M. A. Horning, N. Faghihnia, M. Luke-Zeitoun, and G. A. Brooks Retention of intravenously infused [13C]bicarbonate is transiently increased during recovery from hard exercise J Appl Physiol, November 1, 2007; 103(5): 1604 - 1612. [Abstract] [Full Text] [PDF]

				D. R. Bolster, M. A. Pikosky, P. C. Gaine, W. Martin, R. R. Wolfe, K. D. Tipton, D. Maclean, C. M. Maresh, and N. R. Rodriguez Dietary protein intake impacts human skeletal muscle protein fractional synthetic rates after endurance exercise Am J Physiol Endocrinol Metab, October 1, 2005; 289(4): E678 - E683. [Abstract] [Full Text] [PDF]

				M. P. Engelen, N. E. Deutz, R. Mostert, E. F. Wouters, and A. M. Schols Response of whole-body protein and urea turnover to exercise differs between patients with chronic obstructive pulmonary disease with and without emphysema Am. J. Clinical Nutrition, April 1, 2003; 77(4): 868 - 874. [Abstract] [Full Text] [PDF]

				L. S. Lamont, A. J. McCullough, and S. C. Kalhan Gender differences in leucine, but not lysine, kinetics J Appl Physiol, July 1, 2001; 91(1): 357 - 362. [Abstract] [Full Text] [PDF]

				A. H. Forslund, A. E. El-Khoury, R. M. Olsson, A. M. Sjodin, L. Hambraeus, and V. R. Young Effect of protein intake and physical activity on 24-h pattern and rate of macronutrient utilization Am J Physiol Endocrinol Metab, May 1, 1999; 276(5): E964 - E976. [Abstract] [Full Text] [PDF]

				L. S. Lamont, A. J. McCullough, and S. C. Kalhan Comparison of leucine kinetics in endurance-trained and sedentary humans J Appl Physiol, January 1, 1999; 86(1): 320 - 325. [Abstract] [Full Text] [PDF]

				A MacDonald, G W Rylance, D Asplin, S K Hall, and I W Booth Does a single plasma phenylalanine predict quality of control in phenylketonuria? Arch. Dis. Child., February 1, 1998; 78(2): 122 - 126. [Abstract] [Full Text]