Muscle glycogenolysis during exercise: dual control by epinephrine and contractions
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Muscle glycogenolysis during exercise : dual control by epinephrine and contractions. / Richter, Erik A.; Ruderman, N B; Gavras, H; Belur, E R; Galbo, H.
In: American Journal of Physiology, Vol. 242, No. 1, 1982, p. E25-E32.Research output: Contribution to journal › Journal article › peer-review
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TY - JOUR
T1 - Muscle glycogenolysis during exercise
T2 - dual control by epinephrine and contractions
AU - Richter, Erik A.
AU - Ruderman, N B
AU - Gavras, H
AU - Belur, E R
AU - Galbo, H
PY - 1982
Y1 - 1982
N2 - The interaction of epinephrine and contractions on muscle metabolism was studied in the isolated perfused rat hindquarter. Subtetanic contractions (180/min) through 20 min elicited glycogenolysis and increased phosphorylase a activity. In the soleus, a slow-twitch red muscle, these effects were transient, but when epinephrine at a physiological concentration (2.4 X 10(-8) M) was added to the perfusate, glycogenolysis and phosphorylase activity were sustained throughout contractions. At this high frequency of contractions, the effect of epinephrine was much smaller in the fast-twitch red fibers and not significant in the fast-twitch white fibers of the gastrocnemius muscle. However, during less frequent contractions (30/min) epinephrine increased glycogenolysis and phosphorylase a activity in fast-twitch muscle. The data suggest that epinephrine and muscle contractions exert a dual control of muscle glycogenolysis during exercise: contractions principally stimulate glycogenolysis early in exercise, and a direct effect of epinephrine on muscle is needed for continued glycogenolysis. In addition, epinephrine increased oxygen consumption and glucose uptake in both resting and electrically stimulated hindquarters and, under some conditions, it had a positive inotropic effect on contracting muscle.
AB - The interaction of epinephrine and contractions on muscle metabolism was studied in the isolated perfused rat hindquarter. Subtetanic contractions (180/min) through 20 min elicited glycogenolysis and increased phosphorylase a activity. In the soleus, a slow-twitch red muscle, these effects were transient, but when epinephrine at a physiological concentration (2.4 X 10(-8) M) was added to the perfusate, glycogenolysis and phosphorylase activity were sustained throughout contractions. At this high frequency of contractions, the effect of epinephrine was much smaller in the fast-twitch red fibers and not significant in the fast-twitch white fibers of the gastrocnemius muscle. However, during less frequent contractions (30/min) epinephrine increased glycogenolysis and phosphorylase a activity in fast-twitch muscle. The data suggest that epinephrine and muscle contractions exert a dual control of muscle glycogenolysis during exercise: contractions principally stimulate glycogenolysis early in exercise, and a direct effect of epinephrine on muscle is needed for continued glycogenolysis. In addition, epinephrine increased oxygen consumption and glucose uptake in both resting and electrically stimulated hindquarters and, under some conditions, it had a positive inotropic effect on contracting muscle.
KW - Adenosine Triphosphate
KW - Animals
KW - Electric Stimulation
KW - Epinephrine
KW - Glycogen
KW - Male
KW - Muscle Contraction
KW - Muscles
KW - Norepinephrine
KW - Oxygen Consumption
KW - Perfusion
KW - Phosphocreatine
KW - Rats
KW - Rats, Inbred Strains
M3 - Journal article
C2 - 7058885
VL - 242
SP - E25-E32
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
SN - 0363-6143
IS - 1
ER -
ID: 154760186