Co-existence of myosin heavy chain I and IIa isoforms in human skeletal muscle fibres with endurance training

✍ Scribed by H. Klitgaard; O. Bergman; R. Betto; G. Salviati; S. Schiaffino; T. Clausen; B. Saltin

• Publisher: Springer
• Year: 1990
• Tongue: English
• Weight: 494 KB
• Volume: 416
• Category: Article
• ISSN: 0031-6768
• DOI: 10.1007/bf00370757

✦ Synopsis

The myosin heavy chain (MHC) composition of slng~ibres frc~nm, vastus lateralis was analysed by one-dimensional electrophoresis and immunoblottinq in three groups of young men with distinct difference in physical activity patterns. No major co-existence of MHC isoforms was found in the group with some daily physical activity. In the very sedentary group, however, 19±5% (P,0.05) of the fibres exhibited coexistence of F~C type IIa and IIb. Further, in the endurance trained group co-existence of M~C type I and IIa was manifested in 36±4% (p~0.05) of the fibres. Disuse and extreme usage of muscle both give rise to an elevation in co-expression of MHC isoforms in single muscle fibres but of markedly different combination of isoforms.