De-phosphorylation of MyoD is linking nerve-evoked activity to fast myosin heavy chain expression in rodent adult skeletal muscle.

Elucidating the molecular pathways linking electrical activity to gene expression is necessary for understanding the effects of exercise on muscle. Fast muscles express higher levels of MyoD and lower levels of myogenin than slow muscles, and we have previously linked myogenin to expression of oxidative enzymes. We here report that in slow muscles, compared with fast, 6 times as much of the MyoD is in an inactive form phosphorylated at T115.

PPARdelta expression is influenced by muscle activity and induces slow muscle properties in adult rat muscles after somatic gene transfer.

The effects of exercise on skeletal muscle are mediated by a coupling between muscle electrical activity and gene expression. Several activity correlates, such as intracellular Ca(2+), hypoxia and metabolites like free fatty acids (FFAs), might initiate signalling pathways regulating fibre-type-specific genes. FFAs can be sensed by lipid-dependent transcription factors of the peroxisome proliferator-activated receptor (PPAR) family.

Muscular performance after concentric and eccentric exercise in trained men.

Purpose: We studied previously resistance-trained men and compared the effects of concentric and eccentric training on performance and structural muscle parameters.

Methods: Seventeen trained individuals (age 26.9 +/- 3.

Myogenin induces higher oxidative capacity in pre-existing mouse muscle fibres after somatic DNA transfer.

Muscle is a permanent tissue, and in the adult pronounced changes can occur in pre-existing fibres without the formation of new fibres. Thus, the mechanisms responsible for phenotype transformation in the adult might be distinct from mechanisms regulating muscle differentiation during muscle formation and growth. Myogenin is a muscle-specific, basic helix-loop-helix transcription factor that is important during early muscle differentiation.