Upregulation of myosin heavy chain MHClalpha in rat muscles after unweighting and clenbuterol treatment.
Myosin heavy chain (MHC) mRNA isoforms were quantified in soleus (SOL) and gastrocnemius (GAS) muscles from rats exposed to 14 days of either hindlimb unweighting (HU), clenbuterol treatment (CB), or HU combined with CB treatment (HU-CB). All conditions induced in SOL a shift from slow to faster MHC mRNA isoforms and an upregulation of MHClalpha. Increases were highest with CB, lowest with HU-CB, and coincided mainly with elevations in MHClla mRNA isoforms. The changes in MHC mRNA levels in GAS muscle corresponded to fast-to-faster transitions. Elevations in MHClalpha mRNA were smaller than in SOL and seemed to occur in parallel with decreases in MHClbeta. Taken together, our results suggested that MHClalpha is expressed in transforming rat slow and fast muscles, most likely as an intermediate step between MHClbeta and MHClla.
Stevens
L
L
Laboratory of Neuromuscular Plasticity, University of Sciences and Technologies of Lille, Villeneuve d'Ascq, F-59655, France.
Gohlsch
B
B
Mounier
Y
Y
Pette
D
D
D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002976:Clenbuterol / Q000494:pharmacology*; D019417:Hindlimb Suspension; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015854:Up-Regulation
D000199:Actins; D012333:RNA, Messenger; D018995:Myosin Heavy Chains; D002976:Clenbuterol