Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.9 (glucose-6-phosphatase)
 3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serum glucose, serum protein, serum glutamic oxalacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), and hepatic and renal gluconeogenic enzymes [pyruvate carboxylase (PC), phosphoenolpyruvate carboxykinase (PEPCK), fructose-1,6-diphosphatase (F-1,6-DPase), and glucose-6-phosphatase (G-6-Pase)] were determined in rats treated daily with cadmium alone (0.25 mg/kg X d, injected ip and in rats pretreated with spironolactone (50 mg/kg x d and 100 mg/kg X d, injected sc) prior to cadmium administration. Rats receiving no treatment, propylene glycol, or spironolactone (100 mg/kg X d, injected sc) were used as controls. The daily treatments were continued for an extended period of 90 d, and the rats were sacrificed at 30-, 60-, and 90-d intervals during the continuous daily treatment schedule. Cadmium treatment significantly increased the amount of serum protein, glucose, serum enzymes, and all the four key gluconeogenic enzymes as compared to controls. Pretreatment of rats with spironolactone 6 h prior to cadmium injection daily antagonized the cadmium effect of the above parameters. It appears from these results that spironolactone reduces the effects of cadmium on the key gluconeogenic enzymes in rat kidney and liver.
 ...
PMID:Influence of spironolactone on cadmium-induced changes in hepatic and renal gluconeogenic enzymes in rats. 712 May 5

Gluconeogenic enzymes and substrates were measured in the livers of fasted and suckled newborn pigs in the first 48 h postpartum. The activities at birth of glucose-6-phosphatase, fructose-1,6-diphosphatase, pyruvate carboxylase and phosphoenolpyruvate carboxykinase were, respectively, 70%, 45%, 117% and 35% of adult values. At birth, cytosolic phosphoenolpyruvate carboxykinase represented 35% of total activity, a similar distribution to that in the adult. In suckled piglets, all activities were greater at 24 and 48 h that at birth. In starved piglets, the increases were greater in all cases; the increase in cytosolic phosphoenolpyruvate carboxykinase was much more pronounced than for that for the particulate enzyme, with the former representing more than 50% of total at 48 h. The levels of gluconeogenic enzymes in the piglets in the early neonatal period would appear to be adequate for their needs and do not provide an explanation for their fasting hypoglycaemia. Hepatic levels of lactate, pyruvate, phosphoenolpyruvate, ketone bodies, and amino acids were determined in these piglets. No significant differences were observed in these metabolites between fasted and suckled animals except that glutamine was doubled in fed piglets, Evidence for the metabolic block in the livers of fasted animals was lacking and ketone bodies did not accumulate. These observations suggest that the limitations to gluconeogenesis result from unavailability of energy substrates and/or carbon precursors to the liver or the deficiency in their uptake.
 ...
PMID:Development of gluconeogenic enzymes in the liver of fasting or suckling newborn pigs. 733 8

Studies suggest that liver regeneration is delayed in insulin-deficient animals, but defining a role of insulin as a growth factor in hepatic regeneration has remained elusive. By examining gene expression of hepatectomized liver in type 1 diabetic BB rats, we have identified dramatic changes in the expression of primary or immediate-early growth response genes compared with normal animals. These include altered expression of insulin-regulated genes such as glucose-6-phosphatase (G-6-Pase), phosphoenolpyruvate carboxykinase (PEPCK), and beta-actin, and genes such as CL-6 and map kinase phosphatase-1 (MKP-1) that were previously unlinked to insulin action in animals. Abnormal elevation of mRNAs encoding G-6-Pase, MKP-1, and PEPCK in the time 0 diabetic liver results in decreased induction after partial hepatectomy. Other genes, such as CL-6 and beta-actin, are induced at a lower level in the hepatectomized diabetic animals. The net effect is a blunting of the immediate-early gene response after partial hepatectomy in diabetic animals. As determined by DNA synthesis assays, the regenerative capacity of insulin-deficient BB diabetic livers is reduced, and this defect is corrected at least in part by insulin therapy. These findings suggest that because of insulin deficiency, common intracellular signaling pathways that are required for both metabolism and mitogenesis are aberrant in the type 1 diabetic liver and, as a result, the regenerative response is deficient.
 ...
PMID:Blunting of the immediate-early gene and mitogenic response in hepatectomized type 1 diabetic animals. 748 83

The activity and some kinetic parameters of the key enzymes of the glycolysis, the gluconeogenesis and the amino acid catabolism from the liver of male and female mink have been determined and compared to the corresponding activities from rat and cat. The activities of glucose-6-phosphatase and pyruvate kinase are dependent on sex, both being higher in females. Except for pyruvate carboxylase the glycolytic and the gluconeogenic enzyme activities of the mink are higher than those of rat and cat; especially the activities of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase are markedly higher. The activities of glutamate dehydrogenase and glutamate oxaloacetate transaminase are smaller than the corresponding activities of rat but higher than those of cat. The results suggest that mink has a high capacity for gluconeogenesis compared to rat.
 ...
PMID:Activities of carbohydrate and amino acid metabolizing enzymes from liver of mink (Mustela vison) and preliminary observations on steady state kinetics of the enzymes. 758 47

In the present study, the ontogenic changes in gluconeogenic enzyme activities and in hepatic glycogen and beta-adrenergic receptor levels were investigated in fetal pigs from 70 days of gestation until delivery at term (114 +/- 2 days). The values were compared with those observed in fetuses infused subcutaneously with cortisol for 6 days beginning at 82-84 or 92-94 days of gestation. Tissue glucose-6-phosphatase (G6Pase) activity increased with increasing gestational age in the liver, kidney and duodenum of control fetal pigs. At birth, there was a further increase in G6Pase activity in the liver but not in the kidney or duodenum. In the kidney, there was a similar gestational increase in phosphoenolpyruvate carboxykinase (PEPCK) activity. These changes in enzyme activities closely paralleled the prepartum increase in fetal plasma cortisol and were accompanied by increases in hepatic glycogen content and beta-adrenergic receptor density. At 98-100 days, there were significant increases in G6Pase activity in the liver, kidney and duodenum of the cortisol-infused fetuses, whereas at 88-90 days only renal G6Pase was significantly elevated by cortisol infusion. Cortisol infusion also increased hepatic beta-receptor density at 88-90 days and hepatic glycogen content at both gestational ages. There were no changes in hepatic PEPCK, hepatic or renal fructose diphosphatase and aspartate amino transferase activities during cortisol infusion or with increasing gestational age. When the data from all the piglets were combined, irrespective of age or treatment, there were significant positive correlations between log plasma cortisol and G6Pase activity in the liver, kidney and duodenum. Similar positive correlations were observed between hepatic beta-adrenoceptor density and log plasma cortisol and between the latter values and the hepatic glycogen content. These findings show that cortisol induces tissue G6Pase activity in the fetal pig and suggest that the prepartum rise in endogenous cortisol may be responsible for the increase in fetal glucogenic capacity observed towards term in this as in other species.
 ...
PMID:The glucogenic capacity of the fetal pig: developmental regulation by cortisol. 764 10

Mice homozygous for the targeted deletion of the c/ebp alpha gene, which expresses the CCAAT/enhancer-binding protein alpha (C/EBP alpha), did not store hepatic glycogen and died from hypoglycemia within 8 hours after birth. In these mutant mice, the amounts of glycogen synthase messenger RNA were 50 to 70 percent of normal and the transcriptional induction of the genes for two gluconeogenic enzymes, phosphoenolpyruvate carboxykinase and glucose-6-phosphatase, was delayed. The hepatocytes and adipocytes of the mutant mice failed to accumulate lipid and the expression of the gene for uncoupling protein, the defining marker of brown adipose tissue, was reduced. This study demonstrates that C/EBP alpha is critical for the establishment and maintenance of energy homeostasis in neonates.
 ...
PMID:Impaired energy homeostasis in C/EBP alpha knockout mice. 765 57

Glucose production and utilization and activities of key enzymes involved in liver and muscle glucose metabolism were studied in post-absorptive streptozotocin-diabetic rats after 12 h of severe hyperglycaemia (17.5 +/- 0.5 mmol/l) and insulinopenia (5 +/- 1 microU/ml). Basal glucose production was increased: 36.6 +/- 3.0 mg.kg.min-1, vs 24.4 +/- 2.5 in controls (p < 0.05); liver glycogen concentration was decreased by 40% (p < 0.05); liver phosphoenolpyruvate carboxykinase and glucose-6-phosphatase activities were increased by 375 and 156%, respectively (p < 0.001 and < 0.01). During a euglycaemic clamp at a plasma insulin level of 200 microU/ml, glucose production was totally suppressed in controls, but persisted at 20% of basal in diabetic rats. In these rats, glucose production was suppressed at a plasma insulin level of 2500 microU/ml. Basal whole body glucose utilization rate, 2-deoxy-1-[3H]-D-glucose ([3H]-2DG) uptake by muscles and muscle glycogen concentrations were similar in both groups, as well as total and active forms of pyruvate dehydrogenase and glycogen synthase activities. During the euglycaemic clamp, the total body glucose utilization rates and [3H]-2DG uptake by muscles were similar in control and diabetic rats at a plasma insulin level of 200 microU/ml, but lower in diabetic rats at a plasma insulin level of 2500 microU/ml. We conclude 1) in recent-onset severely insulinopenic rats, an excessive glucose production via gluconeogenesis prevailed, mainly accounting for the concomitant hyperglycaemia. This excess glucose output cannot be attributed to liver insulin resistance: the gluconeogenic pathway is physiologically less sensitive than glycogenolysis to the inhibition by insulin.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Excessive glucose production, rather than insulin resistance, accounts for hyperglycaemia in recent-onset streptozotocin-diabetic rats. 775 74

3-Mercaptopicolinate (3-MP) inhibits D-glucose-6-phosphate (G6P) phosphohydrolase activity of the glucose-6-phosphatase system (Bode et al. (1993) Biochem. Cell Biol. 71, 113-121). We therefore attempted to maximize the inhibition by varying the physical state of microsomes, the concentration of 3-MP, and the time of preliminary incubation of 3-MP with the enzyme. The inhibition was irreversible and time- and inhibitor-concentration-dependent, with G6P phosphohydrolase activity of intact rat liver microsomes, but there was no inhibition with detergent-treated microsomes. The effectiveness of 3-MP as a time-dependent inhibitor of glucose 6-phosphatase was demonstrated in situ by measuring glycogenolysis in isolated, perfused livers from fed rats. We first exposed the livers to 2 mM 3-MP for 40 min, and then assessed the inhibitory effects on glycogenolysis. It was lowered by 50%. These observations establish that 3-MP at the mM level may be useful as an experimental probe in the study of the role(s) of G6P in the regulation of glycogenolysis as well as glycogenesis. Further, they validate the use of much lower (microM) concentrations of 3-MP to block gluconeogenesis (at the phosphoenolpyruvate carboxykinase step) without interfering with glucose 6-phosphatase. We also explored the mechanism of 3-MP inhibition. The time-dependent inhibition of carbamoyl-phosphate:glucose phosphotransferase activity with microsomes incubated with 1 mM 3-MP for 60 or 90 min and then assayed with 1 mM carbamoyl phosphate and 180 mM glucose was modest compared with inhibition of G6P phosphohydrolase. When G6P production by carbamoyl-phosphate:glucose phosphotransferase was reduced by decreasing glucose concentration to 60 mM, no inhibition by 3-MP was discernible. There was no inhibition of inorganic pyrophosphatase activity. These studies support the model of time-dependent, irreversible reaction of 3-MP with the G6P translocase component of the glucose-6-phosphatase system.
 ...
PMID:Time-dependent inhibition of glucose 6-phosphatase by 3-mercaptopicolinic acid. 794 52

Chronic effects of benfluorex on some parameters of carbohydrate metabolism have been studied in 24-month-old Sprague-Dawley rats. Treatment once a day for 14 days with 25 mg benfluorex per kg body weight lowered body weight, decreased circulating insulin and resulted in an increase in hepatic glycogen. Measurement of the activities of several important regulatory enzymes of hepatic carbohydrate metabolism showed a significant decrease in the activities of phosphoenolpyruvate carboxykinase and glycogen phosphorylase. The activity of glucose-6-phosphatase, on the other hand, was slightly increased. Taken collectively, our data offer an explanation for the observed inhibition of hepatic glucose production by chronic benfluorex treatment in cases of hyperinsulinemia.
 ...
PMID:Effects of chronic benfluorex treatment on the activities of key enzymes of hepatic carbohydrate metabolism in old Sprague-Dawley rats. 824 Apr 8

The effects of cortisol on hepatic and renal gluconeogenic enzyme activities were investigated in sheep fetuses during late gestation and after experimental manipulation of plasma cortisol levels by fetal adrenalectomy and exogenous infusion of cortisol. Hepatic and renal gluconeogenic enzyme activities increased with increasing gestational age in parallel with the normal rise in fetal cortisol levels towards term (146 +/- 2 days). For the majority of enzymes this increase in activity towards term was prevented when the prepartum cortisol surge was abolished by fetal adrenalectomy and stimulated prematurely in fetuses younger than 130 days by exogenous infusion of cortisol. When the data from all the fetuses were combined irrespective of treatment or gestational age, there were significant positive correlations between the log plasma cortisol concentration in utero and the activities of glucose-6-phosphatase, fructose diphosphatase, phosphoenolpyruvate carboxykinase and aspartate transaminase in the fetal liver and kidney, and pyruvate carboxylase in the fetal liver but not in the kidney. No correlation was observed between log plasma cortisol and alanine aminotransferase activity in either fetal liver or kidney. These findings show that cortisol is a physiological regulator of most of the fetal gluconeogenic enzymes and enhances the glucogenic capacity of the sheep fetus during late gestation.
 ...
PMID:The effects of cortisol on hepatic and renal gluconeogenic enzyme activities in the sheep fetus during late gestation. 832 49


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>