|
|
||||||||
AJP - Endocrinology and Metabolism, Vol 265, Issue 6 E935-E942, Copyright © 1993 by American Physiological Society
ARTICLES |
L. B. Tadros, N. M. Willhoft, P. M. Taylor and M. J. Rennie
Department of Anatomy and Physiology, University of Dundee, Scotland.
The effects of deprivation and supplementation of exogenous glutamine (0.06 and 2.2 mM in the culture medium, respectively) were studied in mononucleated myoblasts and in multinucleated myotubes. Myoblasts cultured in glutamine-deprived medium showed reductions in plating efficiency and myotube fusion index. Myotubes grown in glutamine-supplemented cultures had higher intracellular glutamine concentrations than those grown in glutamine-deprived medium (67 +/- 4.2 vs. 46 +/- 3.6 nmol/mg cell protein, respectively) and glutamine-supplemented myotubes utilized glutamine, whereas glutamine-deprived myotubes released it. Glutamine deprivation for 12 h caused a significant, cycloheximide-blockable increase in the capacity for glutamine uptake via system Nm in both myoblasts and myotubes (maximum velocity increases of 23 +/- 5.3 and 35 +/- 4.2%, respectively), which was reversed by glutamine replenishment. Depriving myotubes of glutamine did not alter the kinetics of uptake of amino acid transport systems A, ASC, or L. Glutamine deprivation resulted in a threefold increase in glutamine synthetase activity, whereas glutaminase activity remained unchanged. System Nm and glutamine synthetase appear to undergo adaptive upregulation in glutamine-deprived muscle cells to compensate for the reduced exogenous glutamine supply.
This article has been cited by other articles:
![]() |
B. Mittendorfer, E. Volpi, and R. R. Wolfe Whole body and skeletal muscle glutamine metabolism in healthy subjects Am J Physiol Endocrinol Metab, February 1, 2001; 280(2): E323 - E333. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. DeMarco, K. Dyess, D. Strauss, C. M. West, and J. Neu Inhibition of Glutamine Synthetase Decreases Proliferation of Cultured Rat Intestinal Epithelial Cells J. Nutr., January 1, 1999; 129(1): 57 - 62. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Wasa, H.-S. Wang, and A. Okada Characterization of L-glutamine transport by a human neuroblastoma cell line Am J Physiol Cell Physiol, June 1, 2002; 282(6): C1246 - C1253. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |