Correlations of glycogen synthase and phosphorylase activities with glycogen concentration in human muscle biopsies. Evidence for a double-feedback mechanism regulating glycogen synthesis and breakdown.

Détails

ID Serval
serval:BIB_C73DBB982F47
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Correlations of glycogen synthase and phosphorylase activities with glycogen concentration in human muscle biopsies. Evidence for a double-feedback mechanism regulating glycogen synthesis and breakdown.
Périodique
Metabolism: clinical and experimental
Auteur(s)
Munger R., Temler E., Jallut D., Haesler E., Felber J.P.
ISSN
0026-0495
Statut éditorial
Publié
Date de publication
1993
Peer-reviewed
Oui
Volume
42
Numéro
1
Pages
36-43
Langue
anglais
Notes
Publication types: Journal Article - Publication Status: ppublish
Résumé
The purpose of this study was to verify in man the relationships of muscle glycogen synthase and phosphorylase activities with glycogen concentration that were reported in animal studies. The upper level of glycogen concentration in muscle is known to be tightly controlled, and glycogen concentration was reported to have an inhibitory effect on synthase activity and a stimulatory effect on phosphorylase activity. Glycogen synthase and phosphorylase activity and glycogen concentration were measured in muscle biopsies in a group of nine normal subjects after stimulating an increase of their muscle glycogen concentration through either an intravenous glucose-insulin infusion to stimulate glycogen synthesis, or an Intralipid (Vitrum, Stockholm, Sweden) infusion in the basal state to inhibit glycogen mobilization by favoring lipid oxidation at the expense of glucose oxidation. Phosphorylase activity increased from 71.3 +/- 21.0 to 152.8 +/- 20.0 nmol/min/mg protein (P < .005) after the glucose-insulin infusion. Phosphorylase activity was positively correlated with glycogen concentration (P = .005 and P = .0001) after the glucose-insulin and Intralipid infusions, respectively. Insulin-stimulated glycogen synthase activity was significantly negatively correlated with glycogen concentration at the end of the Intralipid infusion (P < .005). In conclusion, by demonstrating a negative correlation of glycogen concentration with glycogen synthase and a positive correlation with phosphorylase, this study might confirm in man the double-feedback mechanism by which changes in glycogen concentration regulate glycogen synthase and phosphorylase activities. It suggests that this mechanism might play an important role in the regulation of glucose storage.
Mots-clé
Adult, Biopsy, Blood Glucose, Fat Emulsions, Intravenous, Fatty Acids, Nonesterified, Feedback, Glucose, Glucose Clamp Technique, Glycogen, Glycogen Synthase, Humans, Infusions, Intravenous, Insulin, Male, Muscles, Osmolar Concentration, Phosphorylases
Pubmed
Web of science
Création de la notice
29/01/2008 9:56
Dernière modification de la notice
20/08/2019 16:42
Données d'usage