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Role of skeletal muscle-fibre type in regulation of glucose metabolism in middle-aged subjects with impaired glucose tolerance during a long-term exercise and dietary intervention.

Authors :
Venoj&ärvi, Mika
Puhke, R.
H&äm&äl&äinen, H.
Marniemi, J.
Rastas, M.
Rusko, H.
Nuutila, P.
H&änninen, O.
Aunola, S.
Source :
Diabetes, Obesity & Metabolism; Nov2005, Vol. 7 Issue 6, p745-754, 10p
Publication Year :
2005

Abstract

Aim: The aim of this study was to investigate the role of skeletal muscle fibre type in the regulation of glucose metabolism in middle-aged obese subjects with impaired glucose tolerance (IGT) during a 2-year exercise and dietary intervention. Methods: Muscle biopsies (musculus vastus lateralis) were taken from 22 subjects belonging to the intervention group of the Finnish Diabetes Prevention Study [ 1 ]. According to their myosin heavy chain (MHC) profile at the baseline, the subjects were divided into two groups: IGT<subscript>slow</subscript> (n = 10) with a high proportion of MHC I isoforms and IGT<subscript>fast</subscript> (n = 12) with a high proportion of MHC II isoforms in the vastus lateralis muscle. The intervention consisted of dietary counselling, strength and power training and/or aerobic exercise. The amount of exercise was the same in both groups; the exercise frequency was 5.1 ± 2.7 h/week in the IGT<subscript>slow</subscript> and 5.1 ± 2.8 h/week in the IGT<subscript>fast</subscript> group. Results: Fasting glucose (p < 0.05), 2-h glucose (p < 0.05), fasting insulin (p < 0.05), haemoglobin A1c (HbA<subscript>1c</subscript>) (p < 0.01) and insulin resistance (p < 0.05) [homeostasis model assessment for insulin resistance (HOMA-IR)] decreased in the IGT<subscript>fast</subscript> group, whereas only the 2-h glucose and HbA<subscript>1c</subscript> concentrations decreased in the IGT<subscript>slow</subscript> group. The amount of the glycogen synthase kinase-3-αβ (GSK-3-αβ) decreased in the IGT<subscript>fast</subscript> group (p < 0.05). Exercise training increased the lactate dehydrogenase (LDH) (p < 0.01), LDH-1 (p < 0.05) and citrate synthase (CS) (p < 0.05) activities in the vastus lateralis muscle in the IGT<subscript>slow</subscript> group, but only the CS activity (p < 0.05) in the IGT<subscript>fast</subscript> group. Conclusions: The glucose metabolism improved both in the IGT<subscript>slow</subscript> and IGT<subscript>fast</subscript> group during the 2-year exercise and dietary intervention. The change was more prominent in the IGT<subscript>fast</subscript> group than in the IGT<subscript>slow</subscript> group, associated with the decrease of the GSK-αβ protein expression in skeletal muscle. The exercise training improved both glycolytic and oxidative capacity in the vastus lateralis muscle. The glycolytic capacity improved in the IGT<subscript>slow</subscript> group and the oxidative capacity in both groups. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
14628902
Volume :
7
Issue :
6
Database :
Complementary Index
Journal :
Diabetes, Obesity & Metabolism
Publication Type :
Academic Journal
Accession number :
18473528
Full Text :
https://doi.org/10.1111/j.1463-1326.2004.00466.x