Document Type

Article

Publication Date

11-1-1991

Abstract

Denervation rapidly (within 24 h) induces insulin resistance of several insulin-responsive pathways in skeletal muscle, including glucose transport; resistance is usually maximal by 3 d. We examined the effect of denervation on the expression of two glucose transporter isoforms (GLUT-1 and GLUT4) in rat hindlimb muscle; GLUT4 is the predominant species in muscle. 1 d postdenervation, GLUT-1 and GLUT4 mRNA and protein concentrations were unchanged. 3 and 7 d postdenervation, GLUT4 mRNA and protein (per microgram DNA) were decreased by 50%. The minor isoform, GLUT-1 mRNA increased by S00 and 100%, respectively, on days 3 and 7 while GLUT-1 protein increased by - 60 and - 100%. The data suggest that the insulin resistance of glucose transport early after denervation does not reflect a decrease in total glucose transporter number, however, decreased GLUT4 expression may contribute to its increased severity after 3 d. Parallel decreases in GLUT-4 mRNA and GLUTA protein postdenervation are consistent with pretranslational regulation; GLUT-1 expression may be regulated pre- and posttranslationally. The cell type(s) which overexpress GLUT-1 postdenervation need to be identified. Nervous stimuli and/or contractile activity may modulate the expression of GLUT-i and GLUT4 in skeletal muscle tissue.

Comments

Article written by researchers from the Divisions of Endocrinology, Metabolism and Nutrition, and Cardiology, Department of Medicine, Gazes Cardiac Research Institute, and Department of Biochemistry and Molecular Biology, Medical University of South Carolina. Published in the Journal of Clinical Investigation, November 1991, volume 88, pages 1546-1552. Includes abstract, references, tables, diagrams, and black-and-white photographic illustrations.

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