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)

The activities and zonal distribution of key enzymes of carbohydrate metabolism were studied in livers of diabetic rats. 48 h after alloxan treatment the following alterations were observed, intermediate values being reached after 24 h: Blood glucose, acetoacetate and beta-hydroxybutyrate were increased to more than 500%; liver glycogen was reduced to about 10%. Portal vein insulin was reduced to below 10%, portal glucagon was increased to almost 200%. The glucogenic enzymes phosphoenolpyruvate carboxykinase and glucose-6-phosphatase were enhanced to 320% and 150%, respectively. The glycolytic enzymes glucokinase and pyruvate kinase L (differentiated from the M2 isoenzyme with a specific anti-L-antibody) were lowered to 50% and 75%, respectively. The citrate cycle enzyme succinate dehydrogenase remained unchanged. The normal periportal to perivenous gradient of phosphoenolpyruvate carboxykinase of about 3:1, as measured in microdissected tissue samples, was enhanced to about 4:1 with activities elevated to 230% and 190%, respectively, in the two zones. The normal periportal to perivenous gradient of pyruvate kinase L of about 1:1.7, as determined with the microdissection technique, was reduced to about 1:1.4 with levels lowered to 55% and 45%, respectively, in the two zones. The even zonal distribution of pyruvate kinase M2 remained unaltered.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Metabolic zonation in liver of diabetic rats. Zonal distribution of phosphoenolpyruvate carboxykinase, pyruvate kinase, glucose-6-phosphatase and succinate dehydrogenase. 298 84

Activities (mumol X min-1 X g liver) and zonal distributions of key enzymes of carbohydrate metabolism were studied in livers of streptozotocin-diabetic rats and compared to the values in alloxan-diabetes. Streptozotocin led to a non-ketotic diabetes with blood glucose being increased by more than fivefold but ketone bodies being in the normal range, while alloxan produced a ketotic diabetes with blood glucose, acetoacetate and beta-hydroxybutyrate being elevated by more than fivefold. Portal insulin was decreased to about 20% in streptozotocin- and more drastically to about 7% in alloxan-diabetes. Conversely, portal glucagon was increased in the two states to about 250% and 180%, respectively. The glucogenic key enzyme phosphoenolpyruvate carboxykinase (PEPCK) was enhanced in streptozotocin- and alloxan-diabetes to over 300%, while the glycolytic pyruvate kinase L (PKL) was lowered to 65% and 80%, respectively. The normal periportal to perivenous gradient of PEPCK of about 3:1, as measured in microdissected tissue samples, was maintained with elevated activities in the two zones. The normal periportal to perivenous gradient of PKL of 1:1.7 was diminished with lowered activities in the two zones. The glucogenic glucose-6-phosphatase (G6Pase) was increased in streptozotocin- and alloxan-diabetes to 130% and 140%, respectively, while the glucose utilizing glucokinase (GK) was decreased to 60% and 50%, respectively. The normal periportal to perivenous gradient of G6Pase, demonstrated histochemically, remained unaffected. Carnitine palmitoyltransferase (CPT) was increased to over 190% and acetyl-CoA carboxylase (ACC) was decreased to 60% in streptozotocin, non-ketotic diabetes, while the two enzymes were altered more drastically to 400% and 50%, respectively, in alloxan, ketotic diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Gluconeogenic-glycolytic capacities and metabolic zonation in liver of rats with streptozotocin, non-ketotic as compared to alloxan, ketotic diabetes. 302 62

1. Measurements of the activities in rat liver of the four key enzymes involved in gluconeogenesis, i.e. pyruvate carboxylase (EC 6.4.1.1), phosphoenolpyruvate carboxykinase (EC 4.1.1.32), fructose 1,6-diphosphatase (EC 3.1.3.11) and glucose 6-phosphatase (EC 3.1.3.9), have been carried out, all four enzymes being measured in the same liver sample. Changes in activities resulting from starvation and diabetes have been studied. Changes in concentration (activity/unit wet weight of tissue) were compared with changes in the hepatic cellular content (activity/unit of DNA). 2. Each enzyme was found to increase in concentration during starvation for up to 3 days, but only glucose 6-phosphatase and phosphoenolpyruvate carboxykinase showed a significant rise in content. Fructose 1,6-diphosphatase appeared to decrease in content somewhat during the early stages of starvation. 3. There was a marked increase in the concentration of all four enzymes in non-starved rats made diabetic with alloxan or streptozotocin, for the most part similar responses being found for the two diabetogenic agents. On starvation, however, the enzyme contents in the diabetic animals tended to fall, often with streptozotocin-treated animals to values no greater than for the normal overnight-starved rat. Deprivation of food during the period after induction of diabetes with streptozotocin lessened the rise in enzyme activity. 4. The results are compared with other published values and factors such as substrate and activator concentrations likely to influence activity in vivo are considered. 5. Lack of correlation of change in fructose 1,6-diphosphatase with the other enzymes questions whether it should be included in any postulation of control of gluconeogenic enzymes by a single gene unit.
 ...
PMID:A comparison of the effects of diabetes induced with either alloxan or streptozotocin and of starvation on the activities in rat liver of the key enzymes of gluconeogenesis. 432 34

The effects of diabetes on hepatic carbohydrate metabolism were investigated in spontaneously diabetic Bio-Breeding Worcester (BB/W) rats. The juvenile-onset-type syndrome displayed by these animals is characterized by beta-cell destruction with subsequent ketosis-prone insulinopenia. Livers from diabetic animals demonstrated increased adenosine 3',5'-cyclic monophosphate levels but subnormal total protein and glycogen content. Isolated perfused livers of diabetic BB/W rats demonstrated an increased rate of glucose production from [14C]lactate and an impaired rate of glycogen synthesis. These data were consonant with hepatic enzyme studies demonstrating markedly increased activities of component gluconeogenic (glucose-6-phosphatase, fructose-1,6-diphosphatase, phosphoenolpyruvate carboxykinase) and glycogenolytic (glycogen phosphorylase) enzymes with decreased activities of glycolytic (hexokinase, pyruvate kinase) and glycogenic (glycogen synthase) enzymes. These findings agree with previous studies using alloxan- and streptozotocin-induced diabetic animals and suggest that accelerated hepatic gluconeogenesis and impaired glucose utilization are pathognomonic of all insulin-deficient diabetic syndromes.
 ...
PMID:Hepatic carbohydrate metabolism in the spontaneously diabetic Bio-Breeding Worcester rat. 625 45

Thermotropic effects on the kinetics of glucose-6-phosphatase (D-glucose-6-phosphate phosphohydrolase, EC 3.1.3.9) activity of hepatic microsomes from normal and alloxan-diabetic rat liver were investigated by determining V, Km and Ki (substrate inhibition) values. Influence of deoxycholate (0.1%) and 1-anilino-8-naphthalene sulfonate (2.5 mM) on the kinetics was also evaluated. 1. Substrate inhibition occurred at 0.06 M for the enzyme from normal rats and at 0.0-0.025 M for the enzyme from diabetic rats. 2. The enzyme from diabetic rats showed a transition that extended between 22.7 and 27 degrees C in the Arrhenius plot (log V vs. T-1) instead of at 19.5 degrees C. 3. Deoxycholate increased the V value of both enzymes without affecting substrate inhibition at all the temperatures but did not completely abolish the transition in the Arrhenius plot of the enzyme from diabetic rats. 4. 1-Anilino-8-naphthalene sulfonate eliminated substrate inhibition and activated the enzyme of normal rats above 27.5 degrees C by increasing both V and Km values. Below this temperature, the enzyme showed biphasic or allosteric kinetics. At low substrate concentrations it was activated as both V and Km values were increased. The enzyme from diabetic rats, on the other hand, was activated at all the temperatures and exhibited linear kinetics. 5. Binding of 1-anilino-8-naphthalene sulfonate to the microsomal fraction increased with decreasing temperature as revealed by the increase of relative fluorescence. The microsomal fraction of diabetic rats showed a more anomalous fluorescence response between 13-18 degrees C. 6. Enthalpy changes for glucose 6-phosphate binding to the inhibition site were slightly larger than binding to the active site. Calculated entropies of activation for transition state complex of glucose-6-phosphatase reaction were fairly large and negative. The free energy of activation (28-30 kcal/mol) was independent of temperature and experimental conditions. 7. In the microsomal fraction (total as well as rough), phospholipid content and fatty acid unsaturation index of phospholipids were decreased after diabetes. The level of free cholesterol remained unchanged but the molar ratio of cholesterol to phospholipid increased. The different thermal response and 1-anilino-8-naphthalene sulfonate interaction to the enzyme from diabetic rat and liver could be ascribed to the altered lipid environment of the enzyme on the endoplasmic reticulum membrane.
 ...
PMID:Hepatic microsomal glucose-6-phosphatase of normal and alloxan-diabetic rats. Thermotropic effects on kinetics and interaction with deoxycholate and 1-anilino-8-naphthalene sulfonate. 626 Jan 94

Two groups of rats were fed diets in which the carbohydrate components was either starch or sucrose. A third group was fed on a stock diet. Half of the animals in each group were made diabetic by injection of either streptozotocin, in two of the groups, or alloxan, in the third group. Both diabetes and sucrose-feeding increased renal gluconeogenesis as indicated by increased activities of fructose-1,6-diphosphatase and glucose-6-phosphatase. Sucrose-feeding increased fatty acid synthesis both in the liver and kidney. However, the effect of diabetes on fatty acid synthesis was different at the two tissue sites. Diabetes, whether induced by streptozotocin or alloxan, decreased fatty acid synthesis in the liver but increased the rate in the kidney. The latter response was obtained for each diet but was additive with the effect of sucrose. We conclude that the effect of diabetes on renal lipid metabolism may reflect, in part, the accelerated glucose flux. The response to both diabetes and sucrose-feeding is also possibly associated with the increased lipid required for the membrane synthesis reported previously.
 ...
PMID:Changes in metabolism of rat kidney and liver caused by experimental diabetes and by dietary sucrose. 709 29

A trial has been performed of a new sweetening agent saccharol, glycosides complex, on energy metabolism in rats with experimental alloxan diabetes. Elevated glucose level observed in rats with insulin insufficiency was associated with hexokinase activity inhibition and changes in the activity of the enzymes involved in glucose-6-phosphate transformation: enhanced activity of glucose-6-phosphatase and glucose-6-phosphate dehydrogenase against inhibition of phosphoglucomutase activity. Introduction of saccharose aggravated the above shifts in the rat liver, whereas saccharol possesses a protective action on hexokinase hepatic reaction and enzymes of glucose-6-phosphate conversion, reduced blood glucose. Positive changes induced by saccharol on energy metabolism in animals with insulin insufficiency can be attributed to the effect of saccharol glycosides.
 ...
PMID:[Effect of saccharol glycosides on energy metabolism in animals with abnormal carbohydrate tolerance]. 797 8

Administration of sodium orthovanadate to diabetic animals exhibits insulin-like effects and has been effective in the reversal of biochemical complications. This study evaluates the effect of sodium orthovanadate (0.6 mg/ml) treatment for 21 days on the hepatic glucose homeostasis and lipid metabolism in alloxan diabetic rats. The activities of two lipogenic enzymes, glucose-6-phosphate dehydrogenase and malic enzyme; and related enzymes, hexokinase and glucose-6-phosphatase were measured in the liver cytosolic fractions of diabetic rats and diabetic rats treated separately with insulin and sodium orthovanadate. The total lipids, triglycerides and cholesterol levels were estimated in the livers of the diabetic and the treated rats. The activities of both the lipogenic enzymes and hexokinase isozymes were significantly decreased, whereas the activity of glucose-6-phosphatase was significantly increased in the diabetic liver. During diabetes, the levels of total lipids and triglycerides increased significantly with a decrease in the cholesterol levels in the liver. Insulin and vanadate were able to restore the altered enzyme activities to almost control levels. Both insulin and vanadate were found to partially restore the altered levels of total lipids, triglycerides and cholesterol in the livers of diabetic rats. The results indicate that vanadate administration to diabetic animals normalizes blood glucose and causes marked improvement of altered lipid metabolism during diabetes. The present study and earlier reports suggest the possible use of vanadate as insulin replacement in the therapy of diabetes when administered at pharmacological doses.
 ...
PMID:Change in the lipid profile, lipogenic and related enzymes in the livers of experimental diabetic rats: effect of insulin and vanadate. 1058 Jun 9

Tinospora cordifolia is widely used in Indian Ayurvedic medicine for treating diabetes mellitus. Oral administration of an aqueous T. cordifolia root extract (TCREt) to alloxan diabetic rats caused a significant reduction in blood glucose and brain lipids. The extract caused an increase in body weight, total haemoglobin and hepatic hexokinase. The root extract also lowers hepatic glucose-6-phosphatase and serum acid phosphatase, alkaline phosphatase, and lactate dehydrogenase in diabetic rats. Thus TCREt has hypoglycaemic and hypolipidaemic effect.
 ...
PMID:Hypoglycaemic and other related actions of Tinospora cordifolia roots in alloxan-induced diabetic rats. 1072 Jul 84

Clinical research has confirmed the efficacy of several plant extracts in the modulation of oxidative stress associated with diabetes mellitus (DM). Oil of Eruca sativa seeds (ESS) is tried for prevention and treatment of DM induced experimentally by alloxan injection. A single dose of alloxan (100 mg/kg) produced a decrease in insulin level, hyperglycemia, elevated total lipids, triglycerides and cholesterol, decreased high-density lipoprotein and hepatic glycogen contents and elevated hepatic glucose-6-phosphatase activity. Concurrent with these changes, there was an increase in the concentration of malondialdehyde and 4-hydroxynonenal in the liver. This oxidative stress was related to a decreased glutathione (GSH) content and superoxide dismutase activity in the liver of alloxan-diabetic rats. ESS oil (0.06 ml/kg) on its own increased significantly hepatic GSH. Daily oral administration of ESS oil 2 weeks before or after diabetes induction ameliorated hyperglycemia, improved lipid profile, blunted the increase in malondialdehyde and 4-hydroxynonenal and stimulated the GSH production in the liver of alloxan-treated rats. We suggested that ESS oil could be used as antidiabetic complement in case of DM. This may be related to its antioxidative properties and to the increase in hepatic GSH.
 ...
PMID:Amelioration of alloxan induced diabetes mellitus and oxidative stress in rats by oil of Eruca sativa seeds. 1105 94


<< Previous 1 2 3 4 5 6 Next >>