Mechanisms limiting glycogen storage in muscle during prolonged insulin stimulation

Journal Article · Tue Nov 01 00:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:6036742

Richter, E A; Hansen, S A; Hansen, B F ^[1]

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1. Univ. of Copenhagen (Denmark)

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 {mu}U/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 from 34.9 {mu}mol{center dot}g{sup {minus}1}{center dot}h{sup {minus}1} at 0 h to 7.5 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-({sup 14}C)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.

• OSTI ID: 6036742
• Journal Information: American Journal of Physiology; (USA), Vol. 255:5; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
GLYCOGEN
METABOLISM
INSULIN
BIOLOGICAL FUNCTIONS
CARBON 14 COMPOUNDS
LACTIC ACID
MUSCLES
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TRACER TECHNIQUES
WATER
CARBOHYDRATES
CARBOXYLIC ACIDS
FUNCTIONS
HORMONES
HYDROGEN COMPOUNDS
HYDROXY ACIDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
ORGANIC ACIDS
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OXYGEN COMPOUNDS
PEPTIDE HORMONES
POLYSACCHARIDES
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