Mechanisms limiting glycogen storage in muscle during prolonged insulin stimulation
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Mechanisms limiting glycogen storage in muscle during prolonged insulin stimulation. / Richter, Erik A.; Hansen, S A; Hansen, B F.
I: American Journal of Physiology (Consolidated), Bind 255, Nr. 5 Pt 1, 1988, s. E621-E628.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › fagfællebedømt
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TY - JOUR
T1 - Mechanisms limiting glycogen storage in muscle during prolonged insulin stimulation
AU - Richter, Erik A.
AU - Hansen, S A
AU - Hansen, B F
PY - 1988
Y1 - 1988
N2 - The extent to which muscle glycogen concentrations can be increased during exposure to maximal insulin concentrations and abundant glucose was investigated in the isolated perfused rat hindquarter preparation. Perfusion for 7 h in the presence of 20,000 microU/ml insulin and 11-13 mM glucose increased muscle glycogen concentrations to maximal values 2, 3, and 3.5 times above normal fed levels in fast-twitch white, slow-twitch red, and fast-twitch red fibers, respectively. Glucose uptake decreased (mean +/- SE) from 34.9 +/- 1.2 mumol.g-1.h-1 at 0 h to 7.5 +/- 0.7 after 7 h of perfusion. During the perfusion muscle glycogen synthase activity decreased and free intracellular glucose and glucose 6-phosphate increased indicating that glucose disposal was impaired. However, glucose transport as measured by the uptake of 3-O-[14C]methyl-D-glucose was also markedly decreased after 5 and 7 h of perfusion compared with initial values. Total muscle water concentration decreased during glycogen loading of the muscles. Mechanisms limiting glycogen storage under maximal insulin stimulation include impaired insulin-stimulated membrane transport of glucose as well as impaired intracellular glucose disposal.
AB - The extent to which muscle glycogen concentrations can be increased during exposure to maximal insulin concentrations and abundant glucose was investigated in the isolated perfused rat hindquarter preparation. Perfusion for 7 h in the presence of 20,000 microU/ml insulin and 11-13 mM glucose increased muscle glycogen concentrations to maximal values 2, 3, and 3.5 times above normal fed levels in fast-twitch white, slow-twitch red, and fast-twitch red fibers, respectively. Glucose uptake decreased (mean +/- SE) from 34.9 +/- 1.2 mumol.g-1.h-1 at 0 h to 7.5 +/- 0.7 after 7 h of perfusion. During the perfusion muscle glycogen synthase activity decreased and free intracellular glucose and glucose 6-phosphate increased indicating that glucose disposal was impaired. However, glucose transport as measured by the uptake of 3-O-[14C]methyl-D-glucose was also markedly decreased after 5 and 7 h of perfusion compared with initial values. Total muscle water concentration decreased during glycogen loading of the muscles. Mechanisms limiting glycogen storage under maximal insulin stimulation include impaired insulin-stimulated membrane transport of glucose as well as impaired intracellular glucose disposal.
KW - Adenosine Triphosphate
KW - Animals
KW - Glucose
KW - Glucosephosphates
KW - Glycogen
KW - Glycogen Synthase
KW - In Vitro Techniques
KW - Insulin
KW - Male
KW - Muscles
KW - Oxygen Consumption
KW - Phosphocreatine
KW - Rats
KW - Rats, Inbred Strains
KW - Stimulation, Chemical
KW - Time Factors
KW - Water
M3 - Journal article
C2 - 3142271
VL - 255
SP - E621-E628
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
SN - 0363-6143
IS - 5 Pt 1
ER -
ID: 154757367