Prednisolone, a cortisol analogue, was given intraperitoneally to rats with 5, 10 or 15 doses of 5 mg. per kg. of body weight per day. Sacrificing the animals 24 hours after the last injection, unfixed frozen sections from small pieces of liver tissue were incubated and stained by a modification from the method of Wachstein and Meisel(1965) for glucose-6-phosphatase (G-6-Pase) activity. Some of the tissue blocks were processed for staining with hematoxylin and eosin for histopathological observation. Glucose-6-phosphatase activity, being represented histochemically by brownish-black deposits, was progressively increased after administrations 5 or 10 times. With 15 doses of prednisolone the general histochemical picture of G-6-Pase activity appeared to be similar to that of the control group, except for a different distribution of hepatocytes possessing strong activity. In prednisolone treated rats, the swollen hepatocytes showed a marked, cytoplasmic vacuolization and nuclear pyknosis, particularly in the periportal and midzonal areas of hepatic lobules. Some discussion of the G-6-Pase corticosteroids are presented in terms of their metabolic effects.
Animal ; Glucose-6-Phosphatase/analysis* ; Liver/drug effects ; Liver/enzymology* ; Male ; Prednisolone/pharmacology* ; Rats

OBJECTIVETo investigate the mutation of glucose-6-phosphatase gene (G6PC gene) in a patient with glycogen storage disease Ⅰa.

METHODSPCR was used to amplify all five exons of G6PC gene. The PCR products were directly sequenced to detect the mutations.

RESULTSA heterozygous 743G>A mutation was found in the patient and his mother, resulting in the substitution of glycine (G) by arginine (R) in codon 222(G222R) in the putative membrane-spanning domain in human G6Pase, but not in his father and his sister.

CONCLUSIONSG222R mutation in G6PC gene was first identified in a patient with glycogen storage disease Ⅰa in mainland China.

Child, Preschool ; Glucose-6-Phosphatase ; genetics ; Glycogen Storage Disease Type I ; genetics ; Humans ; Male ; Mutation ; Sequence Analysis, DNA

OBJECTIVETo investigate the influence and significance of gastric bypass surgery on hepatic gluconeogenesis in type 2 diabetic Goto Kakizaki(GK) rats.

METHODSForty GK rats were randomly divided into Roux-en-Y gastric bypass group(group A) and sham operation group(group B). Differences in glucose tolerance experiment(OGTT) at preoperative and postoperative 1, 2 and 4 weeks were compared and weight was recorded. Glycated hemoglobin levels were measured preoperatively and 4 weeks postoperatively. The animals were sacrificed 4 weeks after surgery and liver tissues were harvested to detect the relative expression of mRNA and protein of glucose 6 phosphatase(G-6-P) and phosphoenol pyruvate kinase(PEPCK) with RT-PCR and Western blot.

RESULTSFasting blood glucose levels were 6.5, 4.9, and 4.7 mmol/L in group A, and were 10.3, 10.4, and 12.5 mmol/L in group B, and the differences between two groups were statistically significant(P<0.05). The blood glucose level at 2 h after stomach lavage were 8.3, 6.4 and 5.5 mmol/L in group A, and were 21.4, 23.8 and 24.7 mmol/L in group B at postoperative 1, 2, 4 weeks, and the differences between two groups were statistically significant(P<0.05). The glycosylated hemoglobin at postoperative 4 weeks was(6.8±1.0)%, significantly lower than that in group B[(7.9±0.8)%, P<0.05]. Hepatic G-6-P and PEPCK mRNA relative expression at postoperative 4 weeks was reduced by 21.0% and 25.9% respectively as compared to group B, and the protein expression reduced as well. Immunohistochemistry showed that hepatic glycogen sedimentary in group A increased significantly.

CONCLUSIONThe relative mRNA and protein level of key enzymes of hepatic gluconeogenesis are significantly decreased after Roux-en-Y gastric bypass surgery and hepatic gluconeogenesis is reduced, which may be a potential mechanism of the decrease of blood glucose.

Animals ; Blood Glucose ; analysis ; Diabetes Mellitus, Experimental ; metabolism ; surgery ; Diabetes Mellitus, Type 2 ; metabolism ; surgery ; Gastric Bypass ; Gluconeogenesis ; Glucose-6-Phosphatase ; metabolism ; Glycated Hemoglobin A ; metabolism ; Intracellular Signaling Peptides and Proteins ; metabolism ; Liver ; enzymology ; Male ; Phosphoenolpyruvate Carboxykinase (GTP) ; metabolism ; Rats

OBJECTIVETo explore the molecular mechanism of type 2 diabetes in intrauterine growth restricted adult rats through determination of blood glucose and expression of gluconeogenic enzymes in liver.

METHODSMale intrauterine growth restriction (IUGR) offspring induced by maternal protein-malnutrition and normal controls were studied. The body weights of offspring rats were weighted from birth to 12 weeks of age. Fasting plasma glucose and insulin levels were determined by glucose oxidase method and enzyme-linked immunosorbent assay (ELISA) respectively at 1 week, 8 weeks, and 12 weeks. Peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1 alpha), phosphoenolpyruvate carboxykinase (PEPCK), and glucose-6-phosphatase (G6Pase) mRNA and protein levels in liver were measured by real time RT-PCR and Western blot in newborn rats (Week 1) and adult rats (Week 12).

RESULTSBirth weights of IUGR rats were significantly lower than those of controls until 4 weeks later, when IUGR rats caught up to controls. Between 8 and 12 weeks, the growth of IUGR rats surpassed that of controls. No significant differences were observed in blood glucose and insulin levels at newborn rats between the two groups. However, by the end of 8 weeks IUGR rats developed hyperinsulinemia and high insulin resistance index. At the age of 12 weeks, IUGR rats had mild fasting hyperglycemia. In addition, hepatic PGC-1 alpha mRNA and protein levels as well as hepatic mRNA levels of PEPCK and G6Pase at Week 1 and Week 12 in IUGR rats were all significantly higher than those of controls (P<0.05).

CONCLUSIONSAs a result of intrauterine malnutrition, the expression of gluconeogenic genes is exaggerated in offspring. This change stays through adulthood and may contribute to the pathogenesis of type 2 diabetes.

Animals ; Female ; Fetal Growth Retardation ; metabolism ; Gluconeogenesis ; Glucose ; metabolism ; Glucose-6-Phosphatase ; genetics ; Liver ; metabolism ; Male ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; RNA, Messenger ; analysis ; RNA-Binding Proteins ; genetics ; Rats ; Rats, Wistar ; Transcription Factors ; genetics

PURPOSE: Glycogen storage disease type Ia (GSD Ia) is an autosomal recessive disorder of glycogen metabolism caused by glucose-6-phosphatase (G6Pase) deficiency. The clinical manifestations of G6Pase deficiency include growth retardation, hepatomegaly, hypoglycemia, lactic acidemia, hyperlipidemia and hyperuricemia. Many mutations of this gene have been found worldwide in various ethnic groups, establishing the molecular basis of GSD Ia. To elucidate a spectrum of the G6Pase gene mutations in Korean, we analyzed mutations in Korean patients with GSD Ia. METHODS: Both alleles of 9 unrelated GSD 1a patients were studied by PCR and direct DNA sequencing methods. In all patients, GSD 1a was diagnosed by the enzyme assay for the liver biopsy specimen. RESULTS: In Korean, the most prevalent mutation was g727t substitution in exon 5, which has been reported to cause abnormal mRNA splicing: Sixteen out of 18 alleles were found to have this mutation. In addition, we identified one novel mutation, a c611g, converting a proline to an alanine at codon 178. CONCLUSION: Our findings suggest that a screening for the g727t mutation by noninvasive molecular method can detect most cases of GSD Ia in Korean patients.
Alanine ; Alleles ; Biopsy ; Codon ; Enzyme Assays ; Ethnic Groups ; Exons ; Glucose-6-Phosphatase ; Glycogen Storage Disease* ; Glycogen* ; Hepatomegaly ; Humans ; Hyperlipidemias ; Hyperuricemia ; Hypoglycemia ; Liver ; Mass Screening ; Metabolism ; Polymerase Chain Reaction ; Proline ; RNA, Messenger ; Sequence Analysis, DNA

Transferrin receptor (TR) performs the major function of binding and internalizing its specific iron-loaded ligand, transferrin, and its expression is closely linked to the proliferation status of the cell. This study was undertaken to elucidate TR expression in the hyperplastic lesion of hepatocyte in chemically induced hepatic carcinogenesis. The resistant hepatocyte model was chosen for a rat model of carcinogenesis and Sprague-Dawley rats were divided into the following groups: the control groups of normal diet and iron-rich diet with or without hydroxyquinoline and the groups of carcinogen alone and carcinogen plus iron-rich diet with or without administration of hydroxyquinoline. Microscopic changes in the liver, expression of transferrin receptor and glucose-6-phosphatase were studied. The hepatocyte of the control group showed both cytoplasmic and membranous expression of TR. The liver of rats fed on high iron diet accumulated iron and the expression of TR was down regulated by intrahepatic iron accumulation. In the carcinogen administered group the resistant hepatocyte of hyperplastic lesion revealed strong membranous expression of TR and failed to accumulate iron in spite of high iron diet but in contrast the surrounding non-resistant hepatocyte expressed TR in both the membrane and cytoplasm and stored iron when fed on high iron diet. The strong membranous expression of TR is one of the characteristics of the resistant hepatocyte of hyperplastic lesion and it seems to be related to the inability to accumulate iron in spite of a high iron diet.
Animal ; Glucose-6-Phosphatase/metabolism ; Immunohistochemistry ; Iron/analysis/pharmacology ; Liver/chemistry/enzymology/pathology ; Liver Neoplasms, Experimental/enzymology/*ultrastructure ; Male ; Rats ; Rats, Sprague-Dawley ; Receptors, Transferrin/*biosynthesis ; Support, Non-U.S. Gov't

PURPOSE: Glycogen storage disease type Ia (GSD Ia) is an autosomal recessive disease characterized by hepatosplenomegaly, short stature, hypoglycemia, hyperuricemia and lactic academia. It is caused by mutations of glucose-6-phosphatase (G6Pase) gene located on chromosome 17q21. The study were undertaken to investigate clinical manifestations and genotype as well as to evaluate the effects of uncooked corn starch (UCCS) on height growth of pubertal and prepubertal subjects with GSD Ia. METHODS: We analyzed clinical data from 24 GSD Ia patients retrospectively by medical record review. Height standard deviation score (Ht-SDS) was calculated from 13 GSD Ia patients under age 15 treated with UCCS and followed-up over 1 year. DNA isolation, PCR reaction and DNA sequencing analysis were performed in all studied patients. RESULTS: Hypertriglyceridemia (100%), elevated liver enzyme (85%), hyperuricemia (48%), hypercholesterolemia (45%), anemia (45%) were major laboratory findings in studied population. Four different mutations of G6Pase gene in 48 alleles were identified. C.648G>T mutation was the predominant mutation, allele frequency of which was 78.6% (33 alleles). The other mutations were p.Phe51Ser, p.Gly222Arg, p.Gly122Asp. The p.Phe51Ser was a novel mutation. Mean Ht-SDS at diagnosis and two years after UCCS treatment were -2.04+/-1.69 and -0.72+/-1.12 respectively, which were statistically significant (P=0.036). CONCLUSION: The genotype of the G6Pase gene was nearly homogeneous in Korean patients with GSD Ia. Molecular analysis of the G6Pase gene will be the diagnosis of choice since the c.648G>T mutation accounts for 78.6% of mutations in Korean patients with GSD Ia. UCCS treatment has a beneficial effect on height growth of children and adolescents with GSD Ia.
Adolescent ; Alleles ; Anemia ; Child ; Diagnosis ; DNA ; Gene Frequency ; Genotype ; Glucose-6-Phosphatase ; Glycogen Storage Disease* ; Glycogen* ; Humans ; Hypercholesterolemia ; Hypertriglyceridemia ; Hyperuricemia ; Hypoglycemia ; Liver ; Medical Records ; Polymerase Chain Reaction ; Retrospective Studies ; Sequence Analysis, DNA ; Starch* ; Zea mays*

Diabetes is a global threat threatening human health in the world, with an increasing incidence rate in recent years. The disorder of glucose metabolism is one of the major factors. As relevant glucose metabolic enzymes such as alpha-glucosidase, glucose-6-phosphatase (G-6-P), glycogen phosphorylase (GP) and glycogen synthase kinase-3 (GSK-3) get involved in and control the process of glucose metabolism, the regulation of the activity of glucose metabolic enzymes is of significance to the treatment of diabetes. Traditional Chinese medicines (TCMs) have been widely researched because of their low toxicology and high efficiency, and many extracts and components from TCMs have been proven to be regulators of glucose metabolic enzymes. Compared with anti-diabetic western medicines, anti-diabetic TCMs feature safety, reliability and low price. This essay summarizes the anti-diabetic effect of TCMs on regulating glucose metabolic enzymes.
Animals ; Diabetes Mellitus ; drug therapy ; enzymology ; metabolism ; Drugs, Chinese Herbal ; analysis ; therapeutic use ; Enzyme Activators ; analysis ; therapeutic use ; Enzyme Inhibitors ; analysis ; therapeutic use ; Glucose ; metabolism ; Glucose-6-Phosphatase ; metabolism ; Glycogen Synthase Kinase 3 ; metabolism ; Humans ; Hypoglycemic Agents ; analysis ; therapeutic use ; alpha-Glucosidases ; metabolism

OBJECTIVEIntrauterine growth retardation (IUGR) is associated with insulin resistance in later life but the mechanism remains unclear. To explore the molecular mechanism of insulin resistance, we determined the expression of gluconeogenic enzymes as well as the expression of transcription factor which promotes gluconeogenesis in the liver of IUGR rats.

METHODSRat model of IUGR was established by maternal proteindouble ended arrowmalnutrition. Hepatic mRNA levels of the key enzymes for gluconeogenesis, PEPCK and G6Pase, and of peroxisome proliferator-activated receptor-gammacoactivator (PGC) -1alpha were measured by RT- PCR in male IUGR pup rats at 3 and 8 weeks of their lives. Hepatic PGC-1alpha protein levels were determined by Western blot.

RESULTSThe average birth weights of the IUGR group (4.97+/-0.83 g) were significantly lower than normal controls (6.54+/-0.52 g) (P<0.01). Until to 4 weeks of age, the weights of the IUGR rats increased to the control level and were higher than normal controls at 8 weeks of age (P<0.05). There were no significant differences in blood glucose and insulin concentrations between the IUGR rats and normal controls at 3 weeks of age. By 8 weeks of age, the IUGR rats showed high insulin concentrations (P<0.01) and high insulin resistance index (P<0.05) compared with the controls. Hepatic PGC-1alpha mRNA and protein levels as well as hepatic mRNA levels of PEPCK and G6Pase in IUGR rats significantly increased at 3 and 8 weeks compared with controls.

CONCLUSIONSAn increased PGC-1alpha expression may contribute to increased mRNA levels of PEPCK and G6Pase, and thus induce the development of insulin resistance in later life in IUGR rats.

Animals ; Female ; Fetal Growth Retardation ; metabolism ; Gluconeogenesis ; Glucose-6-Phosphatase ; genetics ; Insulin Resistance ; Liver ; enzymology ; Male ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; Phosphoenolpyruvate Carboxykinase (GTP) ; genetics ; RNA, Messenger ; analysis ; RNA-Binding Proteins ; genetics ; Rats ; Rats, Wistar ; Transcription Factors ; genetics

UNLABELLEDGlycogen storage disease (GSD) type Ia is an autosomal recessive disorder caused by a deficiency of glucose-6-phosphatase (G6Pase). The gene that encodes G6Pase was mapped to 17q21. The molecular genetic basis of GSD type Ia in the mainland Chinese population has not been explored.

OBJECTIVETo analyze the G6Pase gene mutations, and to compare the phenotypic features and the response to the corn starch treatment among patients who share the same mutation.

METHODSWith the consent of the parents and their children, the authors studied 18 families with clinically diagnosed GSD type Ia from our long time follow-up groups. Direct DNA sequencing of all 5 exons and the exon-intron boundaries of G6Pase gene were done on the blood specimens. Seven of the 18 patients, male 2 and female 5, aged 1.5 to 16 years, were homozygous for same mutation. The clinical symptoms, signs and the serum biochemical values before and after treatment were compared in these 7 patients.

RESULTSThe 7 patients were homozygous of G-->T transversion at the nucleotide 727 in exon 5 (G727T), which has previously been reported to cause abnormal splicing. The parents were heterozygous of the G727T mutation. All the patients exhibited typical features of GSD type Ia with variable severity, including hypoglycemia, hepatomegaly, kidney enlargement, growth retardation, bleeding diathesis, lactic acidemia, hyperlipidemia, and hyperuricemia. Two of the patients had repeated hypoglycemic seizures before the age of 2 years. One had moderate splenomegaly when he came to our clinic at the age of 16, the spleen size was reduced to 2 cm below the left costal margin after 5-year treatment. His sister, homozygous of G727T, did not show splenomegaly. One had multiple hepatic adenoma since the age of 5 years. Four had 5-year-delayed bone age when they started treatment at the age of 9 to 16 years, the bone age reached normal after 2 - 3 years treatment. No matter when they started corn starch treatment, the height increase in the first year was most obvious with an average of 10 cm. All the patients had abnormal liver function before treatment, 5 had constant slightly elevated liver enzymes with the treatment. All had normal urinalysis test, but the urine beta(2)- microglobulin was elevated.

CONCLUSIONSG727T mutation may be the major cause of GSD type Ia in China. Patients with the same mutation could have variable phenotypic characteristics, and the response to the corn starch treatment was different. The diagnosis of GSD type Ia can be based on clinical and biochemical abnormalities combined with mutation analysis instead of enzyme assays on liver biopsy.

Adolescent ; Base Sequence ; Child ; Child, Preschool ; China ; DNA ; chemistry ; genetics ; DNA Mutational Analysis ; Family Health ; Female ; Glucose-6-Phosphatase ; genetics ; metabolism ; Glycogen Storage Disease Type I ; enzymology ; genetics ; pathology ; Homozygote ; Humans ; Infant ; Male ; Molecular Sequence Data ; Phenotype ; Point Mutation ; Polymerase Chain Reaction