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Exercise inhibits glucocorticoid-induced glutamine synthetase expression in red skeletal muscles.
Am J Physiol. 1992 Jan; 262(1 Pt 1):C214-20.AJ

Abstract

One purpose of this study was to determine whether the suppression of glucocorticoid-induced glutamine synthetase (GS) gene expression by exercise is localized to fiber types that are known to be primarily recruited during endurance running. A second purpose examined whether denervation, which is associated with a reduction in contractile activity, would upregulate GS expression. Exercise consisted of treadmill running at 31 m/min for 12-16 wk. Glucocorticoid treatment (100 mg/kg body wt hydrocortisone 21-acetate) was administered during the last 11 days of the exercise program. Basal GS expression was lowest (GS enzyme activity, 43 +/- 3 nmol.h-1.mg protein-1; GS mRNA, 1.0 arbitrary units) in the slow-twitch red soleus, a muscle type that is known to resist glucocorticoid-induced muscle wasting, intermediate (74 +/- 10 and 1.7 +/- 0.2) in fast-twitch red quadriceps, a muscle type susceptible to atrophy, and highest (106 +/- 16 and 5.4 +/- 1.3) in fast-twitch white quadriceps, a muscle type known to be most susceptible to atrophy. Hormone treatment increased GS enzyme activity and mRNA by two- to fourfold in all muscle types. Exercise diminished GS enzyme activity and mRNA in the fast-twitch red fibers to 35-70% of sedentary control values in both basal and glucocorticoid-stimulated muscles. The running also reduced GS enzyme activity in hormone-treated slow-twitch fibers but did not alter basal or glucocorticoid-induced GS expression in fast-twitch white fibers. These results indicate that glucocorticoids induce similar relative GS expression across all muscle types, but the low absolute levels of expression in slow-twitch muscles are not related to any atrophy.(

ABSTRACT

TRUNCATED AT 250 WORDS)

Authors+Show Affiliations

College of Kinesiology, University of Illinois, Chicago 60680.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

1346351

Citation

Falduto, M T., et al. "Exercise Inhibits Glucocorticoid-induced Glutamine Synthetase Expression in Red Skeletal Muscles." The American Journal of Physiology, vol. 262, no. 1 Pt 1, 1992, pp. C214-20.
Falduto MT, Young AP, Hickson RC. Exercise inhibits glucocorticoid-induced glutamine synthetase expression in red skeletal muscles. Am J Physiol. 1992;262(1 Pt 1):C214-20.
Falduto, M. T., Young, A. P., & Hickson, R. C. (1992). Exercise inhibits glucocorticoid-induced glutamine synthetase expression in red skeletal muscles. The American Journal of Physiology, 262(1 Pt 1), C214-20.
Falduto MT, Young AP, Hickson RC. Exercise Inhibits Glucocorticoid-induced Glutamine Synthetase Expression in Red Skeletal Muscles. Am J Physiol. 1992;262(1 Pt 1):C214-20. PubMed PMID: 1346351.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Exercise inhibits glucocorticoid-induced glutamine synthetase expression in red skeletal muscles. AU - Falduto,M T, AU - Young,A P, AU - Hickson,R C, PY - 1992/1/1/pubmed PY - 1992/1/1/medline PY - 1992/1/1/entrez SP - C214 EP - 20 JF - The American journal of physiology JO - Am J Physiol VL - 262 IS - 1 Pt 1 N2 - One purpose of this study was to determine whether the suppression of glucocorticoid-induced glutamine synthetase (GS) gene expression by exercise is localized to fiber types that are known to be primarily recruited during endurance running. A second purpose examined whether denervation, which is associated with a reduction in contractile activity, would upregulate GS expression. Exercise consisted of treadmill running at 31 m/min for 12-16 wk. Glucocorticoid treatment (100 mg/kg body wt hydrocortisone 21-acetate) was administered during the last 11 days of the exercise program. Basal GS expression was lowest (GS enzyme activity, 43 +/- 3 nmol.h-1.mg protein-1; GS mRNA, 1.0 arbitrary units) in the slow-twitch red soleus, a muscle type that is known to resist glucocorticoid-induced muscle wasting, intermediate (74 +/- 10 and 1.7 +/- 0.2) in fast-twitch red quadriceps, a muscle type susceptible to atrophy, and highest (106 +/- 16 and 5.4 +/- 1.3) in fast-twitch white quadriceps, a muscle type known to be most susceptible to atrophy. Hormone treatment increased GS enzyme activity and mRNA by two- to fourfold in all muscle types. Exercise diminished GS enzyme activity and mRNA in the fast-twitch red fibers to 35-70% of sedentary control values in both basal and glucocorticoid-stimulated muscles. The running also reduced GS enzyme activity in hormone-treated slow-twitch fibers but did not alter basal or glucocorticoid-induced GS expression in fast-twitch white fibers. These results indicate that glucocorticoids induce similar relative GS expression across all muscle types, but the low absolute levels of expression in slow-twitch muscles are not related to any atrophy.(ABSTRACT TRUNCATED AT 250 WORDS) SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/1346351/Exercise_inhibits_glucocorticoid_induced_glutamine_synthetase_expression_in_red_skeletal_muscles_ L2 - https://journals.physiology.org/doi/10.1152/ajpcell.1992.262.1.C214?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -