Hepatic carbon flux after re-feeding in the glycogen-storage-disease (gsd/gsd) rat.
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ABSTRACT:
SUBMITTER: Holness MJ
PROVIDER: S-EPMC1148646 | biostudies-other | 1987 Dec
REPOSITORIES: biostudies-other
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Project description:The effects of food deprivation on body weight, liver weight, hepatic glycogen content, glycogenolytic enzymes and blood metabolites were compared in young and old phosphorylase b kinase-deficient (gsd/gsd) rats. Although the concentration of glycogen in liver from 9-week-old female gsd/gsd rats (730 mumol of glucose equivalents/g wet wt.) was increased by 7-8% during starvation, total hepatic glycogen was decreased by 12% after 24 h without food. In 12-month-old male gsd/gsd rats the concentration of liver glycogen (585 mumol of glucose equiv./g wet wt.) was decreased by 16% and total hepatic glycogen by nearly 40% after food deprivation for 24 h. Phosphorylase b kinase and phosphorylase a were present at approx. 10% of the control activities in 9-week-old gsd/gsd rats, but both enzyme activities were increased more than 3-fold in 12-month-old affected rodents. It is concluded that the age-related ability to mobilize hepatic glycogen appears to result from the augmentation of phosphorylase b kinase during maturation of the gsd/gsd rat.
| S-EPMC1147208 | biostudies-other
Project description:1. The work investigated hepatic glycogen synthesis and glucose output after the intragastric administration of glucose or glycerol or the provision of chow ad libitum to 48 h-starved euthyroid or hyperthyroid rats. 2. After glucose administration, glycogen synthesis via the indirect pathway [Newgard, Hirsch, Foster & McGarry (1983) J. Biol. Chem. 258, 8046-8052] occurred concomitantly with reversal of glucose flux across the liver and re-activation of pyruvate kinase in the euthyroid controls. Glycogen synthesis was decreased and net glucose output continued in the hyperthyroid rats, but normal re-activation of pyruvate kinase was observed. 3. Use of 3-mercaptopicolinate indicated that the glucose released from liver of hyperthyroid rats was synthesized from substrates metabolized via the gluconeogenic pathway. 4. Hepatic glycogen synthesis was also impaired in hyperthyroid rats after administration of glycerol or chow. Measurement of portal-minus-hepatovenous concentration differences and arterial glucose concentrations after the administration of glycerol in combination with 3-mercaptopicolinate indicated that flux from triose phosphate to glucose 6-phosphate was not decreased. 5. Inhibited glycogen synthesis after chow re-feeding was associated with accelerated re-activation of hepatic pyruvate dehydrogenase complex in the hyperthyroid rats. 6. The results indicate three distinct and independent actions of hyperthyroidism after re-feeding: (i) it inhibits the reversal of glucose flux across the liver normally observed in response to carbohydrate; (ii) it affects glycogen deposition at a site distal to glucose 6-phosphate; (iii) it allows more rapid re-activation of liver pyruvate dehydrogenase complex in response to a mixed diet.
| S-EPMC1148458 | biostudies-other
Project description:Intraperitoneal injection of 3-mercaptopicolinate into 24 h-food-deprived 27-week-old female control (GSD/GSD) rats lowered the concentration of circulating glucose by 66%, but glycerol and lactate concentrations were increased up to 3- and 4-fold respectively. In phosphorylase b kinase-deficient (gsd/gsd) rats the corresponding changes for blood glucose, lactate and glycerol were half those observed in the controls. Although the concentration of liver glycogen (approx. 12%, w/w) in the gsd/gsd rats was not altered during food deprivation, total hepatic glycogen was decreased by 17%. It is suggested that the gradual breakdown of the extensive hepatic glycogen stores during starvation assists in the maintenance of normoglycaemia in the gsd/gsd rat.
| S-EPMC1152812 | biostudies-other
Project description:Previous findings have established a pivotal role for hepatic pyruvate dehydrogenase complex (PDH) in regulating hepatic carbon flux during the starved-to-fed and fed-to-starved nutritional transitions [Holness, McLennan, Palmer & Sugden (1988) Biochem. J. 252, 325-330; Holness & Sugden (1990) Biochem. J. 268, 77-81]. We have therefore examined liver PDH activities during the light and dark phases of the feeding cycle in the adult rat in relation to hepatic glycogenesis, fatty acid synthesis and cholesterogenesis. There was significant synchronous suppression of lipogenesis and glycogenesis during the light phase; rates were restored asynchronously during the dark (feeding) phase. Glycogen concentrations declined during the light phase and increased during the dark phase. Despite quite dramatic changes in rates of glycogen and lipid synthesis and hepatic glycogen concentrations during the light and dark phases, hepatic PDHa (active form) activity remained relatively unchanged. Qualitative and quantitative differences in the pattern of change in rates of synthesis of fatty acid and cholesterol suggested regulation at pathway-specific sites distal to PDH.
| S-EPMC1132598 | biostudies-other
Project description:Hepatic glycogen storage diseases (GSDs) are inborn errors of metabolism whose dietary treatment involves uncooked cornstarch administration and restriction of simple carbohydrate intake. The prevalence of feeding difficulties (FDs) and orofacial myofunctional disorders (OMDs) in these patients is unknown.ObjectiveTo ascertain the prevalence of FDs and OMDs in GSD.MethodsThis was a cross-sectional, prospective study of 36 patients (19 males; median age, 12.0 years; range, 8.0-18.7 years) with confirmed diagnoses of GSD (type Ia = 22; Ib = 8; III = 2; IXa = 3; IXc = 1). All patients were being treated by medical geneticists and dietitians. Evaluation included a questionnaire for evaluation of feeding behavior, the orofacial myofunctional evaluation (AMIOFE), olfactory and taste performance (Sniffin' Sticks and Taste Strips tests), and facial anthropometry.ResultsNine (25%) patients had decreased olfactory perception, and four (11%) had decreased taste perception for all flavours. Eight patients (22.2%) had decreased perception for sour taste. Twenty-six patients (72.2%) had FD, and 18 (50%) had OMD. OMD was significantly associated with FD, tube feeding, selective intake, preference for fluid and semisolid foods, and mealtime stress (p < 0.05). Thirteen patients (36.1%) exhibited mouth or oronasal breathing, which was significantly associated with selective intake (p = 0.011) and not eating together with the rest of the family (p = 0.041). Lower swallowing and chewing scores were associated with FD and with specific issues related to eating behavior (p < 0.05).ConclusionThere is a high prevalence of FDs and OMDs in patients with GSD. Eating behavior, decreased taste and smell perception, and orofacial myofunctional issues are associated with GSD.
| S-EPMC6336547 | biostudies-literature
Project description:Glycogen storage disease type Ia (GSD Ia) is caused by autosomal mutations in glucose-6-phosphatase ? catalytic subunit (G6PC) and can present with severe hypoglycemia, lactic acidosis and hypertriglyceridemia. In both children and adults with GSD Ia, there is over-accumulation of hepatic glycogen and triglycerides that can lead to steatohepatitis and a risk for hepatocellular adenoma or carcinoma. Here, we examined the effects of the commonly used peroxisomal proliferated activated receptor ? agonist, fenofibrate, on liver and kidney autophagy and lipid metabolism in 5-day-old G6pc -/- mice serving as a model of neonatal GSD Ia. Five-day administration of fenofibrate decreased the elevated hepatic and renal triglyceride and hepatic glycogen levels found in control G6pc -/- mice. Fenofibrate also induced autophagy and promoted ?-oxidation of fatty acids and stimulated gene expression of acyl-CoA dehydrogenases in the liver. These findings show that fenofibrate can rapidly decrease hepatic glycogen and triglyceride levels and renal triglyceride levels in neonatal G6pc -/- mice. Moreover, since fenofibrate is an FDA-approved drug that has an excellent safety profile, our findings suggest that fenofibrate could be a potential pharmacological therapy for GSD Ia in neonatal and pediatric patients as well as for adults. These findings may also apply to non-alcoholic fatty liver disease, which shares similar pathological and metabolic changes with GSD Ia.
| S-EPMC7003036 | biostudies-literature
Project description:1. The metabolism of hepatic glycogen, labelled with [6-3H]glucose at day 19.5 of gestation and with 14C from [U-14C]galactose at delivery, was followed for 10 h in food-deprived gsd/gsd and control (GSD/GSD) neonatal rats. 2. In the affected pups glycogen was maintained at 12% (w/w) and there was no loss of incorporated radioactivity. 3. The 3H and 14C in glycogen from the controls were both decreased by 80%, but 14C was removed at 0--5 h and [6-3H]glucose at 5--10 h. 4. Blood glucose concentrations in the unaffected neonatal rats fell from 5.3 mM at 20 min to 1.7 mM after 10 h. In the gsd/gsd pups blood glucose concentration was decreased from 2 mM at birth to 0.3 mM at 2.5 h: it was maintained at 0.8 mM between 5 and 10 h. 5. In neonatal rats that had been dead for 10 h, hepatic glycogen was decreased by 34% in the controls and by 22% in the gsd/gsd pups. These results demonstrate that liver from the affected rats contains glycogenolytic activity, but that it is not expressed in living tissue.
| S-EPMC1158155 | biostudies-other
Project description:Now 15-year-old girl with glycogen storage disease (GSD) type IIIa (OMIM 232400) developed severe left ventricular obstructive hypertrophy and hepatomegaly while treated with frequent cornstarch meals. Subsequently, she was introduced the ketogenic diet; continuous ketosis has been maintained for over the last 4 years. After the introduction of ketogenic diet, a normalization of the cardiomyopathy and improvement of hepatopathy was achieved, with enhanced overall quality of life.
| S-EPMC7371897 | biostudies-literature
Project description:abstract1: Glycogen storage disease type Ia (GSD Ia) is an inborn error of metabolism caused by defective glucose-6-phosphatase (G6PC) activity. GSD Ia patients exhibit severe hepatomegaly due to glycogen and triglyceride (TG) accumulation in the liver. We have previously shown that the activity of Carbohydrate Response Element Binding Protein (ChREBP), a key regulator of glycolysis and de novo lipogenesis, is increased in GSD Ia. In the current study we assessed the contribution of ChREBP to non-alcoholic fatty liver disease (NAFLD) development in a mouse model for hepatic GSD Ia. PMID : 32083759 Abstract2:Glycogen storage disease type 1a (GSD Ia) is an inborn error of metabolism caused by a defect in glucose-6-phosphatase (G6PC) activity, which induces severe hepatomegaly and increases the risk for liver cancer in patients. Hepatic GSD Ia is characterized by constitutive activation of Carbohydrate Response Element Binding Protein (ChREBP), a glucose-sensitive transcription factor that has been proposed as a pro-oncogenic molecular switch that supports tumour progression. Here we studied the contribution of ChREBP signalling on liver disease progression and tumour susceptibility in a mouse model for GSD Ia. Hepatocyte-specific G6pc knockout (L-G6pc-/-) mice were treated with AAV-shChREBP to normalize hepatic ChREBP activity. Hepatic ChREBP normalization induced dysplastic liver growth, massively increased hepatocyte size and sensitized to hepatic inflammation and liver fibrosis in GSD Ia mice. Furthermore, the nuclear levels of the oncoprotein YAP were increased and its transcriptional targets were induced in ChREBP normalized GSD Ia mice. Hepatic ChREBP normalization furthermore induced DNA damage and mitotic activity in GSD Ia mice, while chromosomal instability, cGAS-STING pathway, senescence, and hepatocyte dedifferentiation gene signatures emerged. Upon ChREBP silencing in immortalized human hepatocytes, on the other hand, the induction of YAP target gene expression was paralleled by cell cycle arrest, cell death, and reduced proliferation. In conclusion, our findings indicate that ChREBP activity limits hepatomegaly while protecting against liver disease progression and hepatocellular tumour induction in GSD Ia. These results underline the importance to establish the context-specific roles of ChREBP to define its therapeutic potential. PMID:37085901
2023-04-22 | GSE143357 | GEO
Project description:BackgroundGlycogen storage diseases (GSDs) with liver involvement are classified into types 0, I, III, IV, VI, IX and XI, depending on the affected enzyme. Hypoglycemia and hepatomegaly are hallmarks of disease, but muscular and renal tubular involvement, dyslipidemia and osteopenia can develop. Considering the paucity of literature available, herein we provide a narrative review of these latter forms of GSDs.Main bodyDiagnosis is based on clinical manifestations and laboratory test results, but molecular analysis is often necessary to distinguish the various forms, whose presentation can be similar. Compared to GSD type I and III, which are characterized by a more severe impact on metabolic and glycemic homeostasis, GSD type 0, VI, IX and XI are usually known to be responsive to the nutritional treatment for achieving a balanced metabolic homeostasis in the pediatric age. However, some patients can exhibit a more severe phenotype and an important progression of the liver and muscular disease. The effects of dietary adjustments in GSD type IV are encouraging, but data are limited.ConclusionsEarly diagnosis allows a good metabolic control, with improvement of quality of life and prognosis, therefore we underline the importance of building a proper knowledge among physicians about these rare conditions. Regular monitoring is necessary to restrain disease progression and complications.
| S-EPMC9208159 | biostudies-literature