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Dexamethasone regulates glutamine synthetase expression in rat skeletal musclesThe regulation of glutamine synthetase by glucocorticoids in rat skeletal muscles was studied. Administration of dexamethasone strikingly enhanced glutamine synthetase activity in plantaris and soleus muscles. The dexamethasone-mediated induction of glutamine synthetase activity was blocked to a significant extent by orally administered RU38486, a glucocorticoid antagonist, indicating the involvement of intracellular glucocorticoid receptors in the induction. Northern blot analysis revealed that dexamethasone-mediated enhancement of glutamine synthetase activity involves dramatically increased levels of glutamine synthetase mRNA. The induction of glutamine synthetase was selective in that glutaminase activity of soleus and plantaris muscles was not increased by dexamethasone. Furthermore, dexamethasone treatment resulted in only a small increase in glutamine synthetase activity in the heart. Accordingly, there was only a slight change in glutamine synthetase mRNA level in this tissue. Thus, glucocorticoids regulate glutamine synthetase gene expression in rat muscles at the transcriptional level via interaction with intracellular glutamine production by muscle and to mechanisms underlying glucocorticoid-induced muscle atrophy.
Document ID
19880015745
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Max, Stephen R.
(Maryland Univ. Baltimore., United States)
Konagaya, Masaaki
(Maryland Univ. Baltimore., United States)
Konagaya, Yoko
(Maryland Univ. Baltimore., United States)
Thomas, John W.
(National Inst. of Health Bethesda, MD., United States)
Banner, Carl
(National Inst. of Health Bethesda, MD., United States)
Vitkovic, Ljubisa
(National Inst. of Health Bethesda, Md., United States)
Date Acquired
September 5, 2013
Publication Date
January 1, 1986
Subject Category
Life Sciences (General)
Report/Patent Number
NAS 1.26:182935
NASA-CR-182935
Accession Number
88N25129
Funding Number(s)
CONTRACT_GRANT: NAG2-100
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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