AJP - Endo Add DOIs to your references at manuscript stage!
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Endocrinol Metab 276: E1136-E1145, 1999;
0193-1849/99 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Labow, B. I.
Right arrow Articles by Abcouwer, S. F.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Labow, B. I.
Right arrow Articles by Abcouwer, S. F.
Vol. 276, Issue 6, E1136-E1145, June 1999

Glutamine synthetase expression in muscle is regulated by transcriptional and posttranscriptional mechanisms

Brian I. Labow, Wiley W. Souba, and Steve F. Abcouwer

Surgical Oncology Research Laboratories, Massachusetts General Hospital, and Department of Surgery, Harvard Medical School, Boston, Massachusetts 02114

Skeletal muscle exports glutamine (Gln) and increases the expression of the enzyme glutamine synthetase (GS) in response to physiological stress. Acute stress or direct glucocorticoid administration raises muscle GS mRNA levels dramatically without a parallel increase in GS protein levels. In the lung, this discrepancy is caused by feedback destabilization of the GS protein by its product Gln. It was hypothesized that muscle GS protein levels increase during stress only when the intracellular Gln pool has been depleted. Adult male rats were injected with the glucocorticoid hormone dexamethasone (DEX) to mimic the acute stress response and with the GS inhibitor methionine sulfoximine (MSO) to deplete muscle Gln stores. DEX increased GS mRNA levels by 2.8-fold but increased GS protein levels by an average of only 40%. MSO diminished muscle GLN levels by 68% and caused GS protein levels to rise in accordance with GS mRNA. Chronic stress was mimicked using 6 days of MSO treatment, which produced anorexia, 23% loss of body weight, and 64% decrease in muscle Gln levels, as well as pronounced increases in both muscle GS mRNA (26-fold) and protein levels (35-fold) without elevation of plasma glucocorticoid levels. Calorie-restricted pair-fed animals exhibited lesser increases in muscle GS mRNA (8-fold) and protein levels (5-fold) without a decline in muscle Gln content. Thus regulation of GS expression in both acute and chronic stress involved both transcriptional and posttranscriptional mechanisms, perhaps affected by muscle Gln content.

glutamate-ammonia ligase; dexamethasone; methionine sulfoximine; starvation; gene expression regulation


This article has been cited by other articles:


Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
C. Smith, N. W. Wilson, A. Louw, and K. H. Myburgh
Illuminating the interrelated immune and endocrine adaptations after multiple exposures to short immobilization stress by in vivo blocking of IL-6
Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2007; 292(4): R1439 - R1447.
[Abstract] [Full Text] [PDF]

Home page
 J. Nutr.Home page
B. I. Labow, W. W. Souba, and S. F. Abcouwer
Mechanisms Governing the Expression of the Enzymes of Glutamine Metabolism--Glutaminase and Glutamine Synthetase
J. Nutr., September 1, 2001; 131(9): 2467S - 2474.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
P. Factor, K. Ridge, J. Alverdy, and J. I. Sznajder
Continuous enteral nutrition attenuates pulmonary edema in rats exposed to 100% oxygen
J Appl Physiol, November 1, 2000; 89(5): 1759 - 1765.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online