Myosin heavy chain composition of single fibres from m. biceps brachii of male body builders

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Deutscher übersetzter Titel:Zusammensetzung der schwerkettigen Myosine in isolierten Muskelfasern des m. biceps brachii von maennlichen Bodybuildern
Autor:Klitgaard, H.; Zhou, M.; Richter, E.A.
Erschienen in:Acta physiologica Scandinavica
Veröffentlicht:140 (1990), 2, S. 175-180, Lit.
Format: Literatur (SPOLIT)
Publikationstyp: Zeitschriftenartikel
Medienart: Gedruckte Ressource
Sprache:Englisch
ISSN:0001-6772, 1365-201X
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Erfassungsnummer:PU199302047699
Quelle:BISp

Abstract

The myosin heavy chain (MHC) composition of single fibres from m. biceps brachii of young sedentary men (28 +/- 0.4 years, mean +/- SE, n = 4) and male body builders (25 +/- 2.0 years, n = 4) was analysed with a sensitive one-dimensional electrophoretic technique. Compared with sedentary men, the body builders had a higher proportion of fibres containing only MHC type IIa (36 +/- 4 vs 12 +/- 2; P < 0.05), but a lower proportion of fibres with a coexistence of MHC types IIa and IIb (16 +/- 3 vs 34 +/- 2; P < 0.05) and nearly no fibres containing only MHC type IIb (1 +/- 1 vs 12 +/- 1; P < 0.05). Myofibrillar ATPase histochemistry only demonstrated a trend towards a higher proportion of type IIa fibres (31 +/- 6 vs 25 +/- 6) and a lower proportion of type IIb fibres (18 +/- 5 vs. 26 +/- 6) within the body builders. These results, therefore, suggest an altered expression of MHC isoforms within histochemical type II fibres of human skeletal muscle with body building. Furthermore, in human skeletal muscle differences in expression of MHC isoforms may not always be reflected in the traditional histochemical classification of types I, IIa, IIb and IIc fibres. Verf.-Referat