title: Regulatory role of glucose-6 phosphatase in the repletion of liver glycogen during refeeding in fasted rats.
abstract: We analyzed the biochemical mechanisms involved in the liver glycogen repletion upon refeeding for 360 min in 48 and 96 h-fasted rats. In 48 h-fasted rats, the glycogen synthesis involved a rapid and further sustained induction of glucokinase (GK) (increased twice from 90 min) and a rapid but transient activation of glycogen synthase a (GSa) (maximal increase by 150% at 90 min). It did not involve the inhibition of glycogen phosphorylase a (GPa). In 96 h-fasted rats, the glycogen repletion did not involve the induction of GK for the first 180 min of refeeding. It involved a slow activation of GSa (maximal 150% increase at 180 min) and a rapid inhibition of GPa (significant from 90 min, maximal 50% inhibition by 180 min). In both groups of rats, there was a progressive inhibition of the glucose-6 phosphatase (Glc6Pase) activity (maximal suppression by 30% in both groups at 360 min). These results highlighted a key role for the inhibition of Glc6Pase activity in the liver glycogen repletion upon refeeding.
authors.affiliation: INSERM U. 449, Faculté de Médecine Laennec, rue Guillaume Paradin, 69372, Lyon, France.
authors.forename: C
authors.initials: C
authors.lastname: Minassian
authors.forename: S
authors.initials: S
authors.lastname: Montano
authors.forename: G
authors.initials: G
authors.lastname: Mithieux
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight; D004435:Eating; D005215:Fasting; D005952:Glucose-6-Phosphatase / Q000378:metabolism*; D006003:Glycogen / Q000096:biosynthesis*; D006006:Glycogen Synthase / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D009929:Organ Size; D019518:Postprandial Period; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D006003:Glycogen; D006006:Glycogen Synthase; D005952:Glucose-6-Phosphatase