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UCP3 protein expression is lower in type I, IIa and IIx muscle fiber types of endurance-trained compared to untrained subjects

journal contribution
posted on 01.02.2003, 00:00 authored by Aaron RussellAaron Russell, Glenn WadleyGlenn Wadley, M Hesselink, G Schaart, Sing Lo, B Léger, Andrew GarnhamAndrew Garnham, E Kornips, David Cameron-Smith, J P Giacobino, P Muzzin, Rod SnowRod Snow, P Schrauwen
Uncoupling protein 3 (UCP3) is a muscle mitochondrial protein believed to uncouple the respiratory chain, producing heat and reducing aerobic ATP production. Our aim was to quantify and compare the UCP3 protein levels in type I, IIa and IIx skeletal muscle fibers of endurance-trained (Tr) and healthy untrained (UTr) individuals. UCP3 protein content was quantified using Western blot and immunofluorescence. Skeletal muscle fiber type was determined by both an enzymatic ATPase stain and immunofluorescence. UCP3 protein expression measured in skeletal muscle biopsies was 46% lower ( P=0.01) in the Tr compared to the UTr group. UCP3 protein expression in the different muscle fibers was expressed as follows; IIx>IIa>I in the fibers for both groups ( P<0.0167) but was lower in all fiber types of the Tr when compared to the UTr subjects ( P<0.001). Our results show that training status did not change the skeletal muscle fiber hierarchical UCP3 protein expression in the different fiber types. However, it affected UCP3 content more in type I and type IIa than in the type IIx muscle fibers. We suggest that this decrease may be in relation to the relative improvement in the antioxidant defense systems of the skeletal muscle fibers and that it might, as a consequence, participate in the training induced improvement in mechanical efficiency.

History

Journal

Pfluegers Archiv : European journal of physiology

Volume

445

Issue

5

Pagination

563 - 569

Publisher

Springer-Verlag

Location

Berlin, Germany

ISSN

0031-6768

eISSN

1432-2013

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2003, Kluwer Academic