Insulin action on rates of muscle protein synthesis following eccentric, muscle-damaging contractions.
The purpose of this study was to determine whether eccentric, muscle-damaging contractions affect insulin action on muscle protein synthesis. Male Wistar rats (n = 28) were anaesthetized either once or twice separated by 7 days' rest, and one limb was electrically stimulated to contract eccentrically, while the contralateral limb served as a non-stimulated control. Twenty-four and 48 h after contractions, rates of protein synthesis were assessed in soleus and red or white gastrocnemius muscles during a hindlimb perfusion with or without insulin (20 000 microU mL(-1)). Rates of protein synthesis were not different in non-stimulated muscle, with or without insulin (P > 0.05). In red or white gastrocnemius without insulin, rates of protein synthesis were significantly reduced (P < 0.05) 24 and 48 h after a single session and 48 h after a double session of muscle contractions. However, protein synthesis was normalized with insulin 24 and 48 h after contractions in red, and 48 h after contractions in white gastrocnemius. In soleus muscle, protein synthesis was impaired only 48 h after the second session, but partially restored by insulin (P < 0.05). These results indicate that muscle becomes more sensitive to insulin action on rates of protein synthesis after muscle-damaging contractions.
Fluckey
J D
JD
PANUM Institute, Copenhagen, Denmark.
Asp
S
S
Enevoldsen
L H
LH
Galbo
H
H
D000818:Animals; D004558:Electric Stimulation; D005947:Glucose / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018656:Muscle Fibers, Fast-Twitch / Q000187:drug effects / Q000378:metabolism; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000166:cytology / Q000293:injuries / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D007004:Hypoglycemic Agents; D007328:Insulin; D009124:Muscle Proteins; D005947:Glucose