title: Activity of glycogen synthase and glycogen phosphorylase in normal and cirrhotic rat liver during glycogen synthesis from glucose or fructose.
abstract: Cirrhotic patients often demonstrate glucose intolerance, one of the possible causes being a decreased glycogen-synthesizing capacity of the liver. At the same time, information about the rates of glycogen synthesis in the cirrhotic liver is scanty and contradictory. We studied the dynamics of glycogen accumulation and the activity of glycogen synthase (GS) and glycogen phosphorylase (GP) in the course of 120min after per os administration of glucose or fructose to fasted rats with CCl4-cirrhosis or fasted normal rats. Blood serum and liver pieces were sampled for examinations. In the normal rat liver administration of glucose/fructose initiated a fast accumulation of glycogen, while in the cirrhotic liver glycogen was accumulated with a 20min delay and at a lower rate. In the normal liver GS activity rose sharply and GPa activity dropped in the beginning of glycogen synthesis, but 60min later a high synthesis rate was sustained at the background of a high GS and GPa activity. Contrariwise, in the cirrhotic liver glycogen was accumulated at the background of a decreased GS activity and a low GPa activity. Refeeding with fructose resulted in a faster increase in the GS activity in both the normal and the cirrhotic liver than refeeding with glucose. To conclude, the rate of glycogen synthesis in the cirrhotic liver is lower than in the normal one, the difference being probably associated with a low GS activity.
authors.affiliation: Laboratory of Cellular Pathology, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia. Electronic address: natalia_bezborodkina@mail.ru.
authors.forename: Natalia N
authors.initials: NN
authors.lastname: Bezborodkina
authors.affiliation: Laboratory of Cellular Pathology, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.
authors.forename: Anna Yu
authors.initials: AY
authors.lastname: Chestnova
authors.affiliation: Cathedra of Pharmacology, Saint Petersburg State Chemical Pharmaceutical Academy, St. Petersburg, Russia.
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Okovity
authors.affiliation: Laboratory of Cellular Pathology, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.
authors.forename: Boris N
authors.initials: BN
authors.lastname: Kudryavtsev
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002251:Carbon Tetrachloride / Q000633:toxicity; D005632:Fructose / Q000008:administration & dosage / Q000378:metabolism*; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism*; D018149:Glucose Intolerance; D006003:Glycogen / Q000096:biosynthesis*; D024981:Glycogen Phosphorylase / Q000378:metabolism*; D006006:Glycogen Synthase / Q000378:metabolism*; D015227:Lipid Peroxidation; D008099:Liver / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D008106:Liver Cirrhosis, Experimental / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051381:Rats
chemical_list: D000975:Antioxidants; D005632:Fructose; D006003:Glycogen; D002251:Carbon Tetrachloride; D024981:Glycogen Phosphorylase; D006006:Glycogen Synthase; D005947:Glucose
keywords: Fructose; Glucose; Glycogen; Glycogen phosphorylase; Glycogen synthase; Liver cirrhosis