Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:4.1.1.32 (phosphoenolpyruvate carboxykinase)
4,204 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The ratio of the combined activities of hexokinase (EC 2.7.1.1) and glucokinase (EC 2.7.1.2) to the activity of glucose-6-phosphatase (EC 3.1.3.9) changed in favour of the glycolytic enzymes during pregnancy and at peak lactation. 2. There were no important changes in the ratio of the activity of phosphofructokinase (EC 2.7.1.11) to that of fructose diphosphatase (EC 3.1.3.11). 3. The ratio of the activity of pyruvate kinase (EC 2.7.1.40) to the combined activities of phosphoenolpyruvate carboxylase (EE 4.1.1.32) and pyruvate carboxylase (EC 6.4.1.1) changed in favour of the glycolytic enzyme during pregnancy and at peak lactation, but changed in favour of the gluconeogenic enzymes immediately after parturition. 4. These changes are considered in relation to the changes in food intake and hormonal status that occur during pregnancy and lactation.
...
PMID:The effects of pregnancy and lactation on the activities in rat liver of some enzymes associated with glucose metabolism. 17 Sep 98

During the first 72 h after 67% partial hepatectomy of female Wistar rats (160 g) the specific activities [mumol X min-1 X (g liver)-1] of the glucogenic glucose-6-phosphatase and fructose-bisphosphatase and of the glycolytic hexokinase and 6-phosphofructokinase remained essentially constant. However, the activity of the glycolytic pyruvate kinase (L- plus M2-type) was decreased slightly and that of glucokinase was decreased markedly to below 30%, while the glucogenic phosphoenolpyruvate carboxykinase was increased to over 200%. Between 10 and 40 h after partial hepatectomy, when the proliferation started in the periportal area, a shift of the glucogenic glucose-6-phosphatase-rich zone from its normal periportal to an intermediate or even perivenous position was observed histochemically. After 48 h, when the proliferation was no longer restricted to the periportal zone, the normal glucose-6-phosphatase zonation (as before partial hepatectomy) was restored. Glycogen was degraded rapidly during the first 4 h after operation; it was later repeatedly resynthesized and degraded in correlation with the feeding rhythm of the animals. The zonation of glycogen metabolism was in accord with the observed zonation of glucose-6-phosphatase.
...
PMID:Increase of the gluconeogenic and decrease of the glycolytic capacity of rat liver with a change of the metabolic zonation after partial hepatectomy. 21 1

Streptozotocin treatment (125 mg/kg) in the Chinese hamster induced hyperglycaemia, hypoinsulinaemia, hyperglucagonaemia and changes in body, liver, pancreas, stomach, kidney and adipose tissue weights. The pancreatic reserves of insulin and glucagon in the diabetic animals were low, but stomach glucagon high. These animals showed high levels of phosphoenolpyruvate carboxykinase and low levels of glucokinase, hexokinase, isocitrate dehydrogenase and malic enzyme, but normal levels of pyruvate kinase in the liver. Increases in lactate dehydrogenase subunit B and isozymes 2, 3 and 4 were also observed in the liver, but not in the epididymal fat pad, of the diabetic animals. N-Acetyl-beta-D-glucosaminidase was elevated in plasma, liver and heart, but not in the kidney of the treated animals. Renal alpha-galactosidase and beta-glucosidase were depressed, whereas beta-galactosidase and alpha-glucosidase remained essentially normal. These features indicated that there were considerable differences between the biochemical disorders associated with streptozotocin-diabetes in the Chinese hamster and the published observations in the rat.
...
PMID:Streptozotocin-induced diabetes in the Chinese hamster. Biochemical and endocrine disorders. 59 Jun 51

Chronic (6 days) hyperinsulinaemia in young rats produced lower blood glucose concentrations and augmented body- and liver-weight gain. The insulin-treated rats had increased hepatic activities of citrate-cleavage enzyme, 'malic' enzyme and high-substrate (6.6 mM-phosphoenolpyruvate) pyruvate kinase, and decreased glucose 6-phosphatase. There were no changes in activities of phosphoenolpyruvate carboxykinase, phosphofructokinase, low-substrate (1.3 mM-phosphoenolpyruvate) pyruvate kinase, glucokinase and hexokinase.
...
PMID:Effects of chronic hyperinsulinaemia on hepatic enzymes involved in lipogenesis and carbohydrate metabolism in the young rat. 66 50

1. Measurements have been made of the activities of enzymes of the glycolytic route, the pentose phosphate pathway, the tricarboxylic acid cycle and lipogenesis in liver and adipose tissue from genetically obese (fa/fa) rats and their lean litter mates (fa/ --). The effect of food restriction for a period of three weeks on the enzyme profile of liver and adipose tissue of the obese rat was also studied. 2. The most striking increases in enzyme activity in livers from obese rats were: (a) among enzymes of lipogenesis; ATP-citrate lyase, acetyl-CoA carboxylase, fatty acid synthetase, malate dehydrogenase (decarboxylating) and cytoplasmic glycerolphosphate dehydrogenase; (b) within the pentose phosphate pathway; glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase; (c) within the glycolytic pathway; glucokinase, pyruvate kinase and lactate dehydrogenase. All of these enzymes showed a significant increase in activity on the basis of U/g liver and U/mg DNA. In adipose tissue all the enzymes of lipogenesis, of the glycolytic route, of the oxidative segment of the pentose phosphate pathway and of the tricarboxylic acid cycle were increased when expressed as U/2 fat pads or as U/mg DNA. 3. The restriction of the food intake of obese rats to that consumed by their lean litter mates for periods of three weeks did not produce the expected adaptive decrease in enzymes of lipogenesis; in adipose tissue, only ATP-citrate lyase and malate dehydrogenase (decarboxylating) showed a marked decrease; no significant change was found in adipose tissue or liver of the activities of acetyl-CoA carboxylase and fatty acid synthetase, when expressed on a cell basis (U/mg DNA). The non-oxidative enzymes of the pentose phosphate pathway and enzymes involved in glycerogenesis (pyruvate carboxylase, malate dehydrogenase and phosphoenolpyruvate carboxykinase) all increased in adipose tissue from limit-fed obese rats. 4. The rate of conversion of specifically labelled glucose to (14C)O2 and 14C-labelled lipid by pieces of adipose tissue and by liver slices was also measured. Insulin caused an increase in the conversion of (1-14C)glucose to (14C)O2 and 14C-labelled lipid in obese rats fed ad libitum, limit-fed rats and in their lean litter mates. 5. The results are discussed in relation to the raised insulin and hypothyroid state of the obese rat. The effect of this altered hormonal status on the activity of cyclic nucleotide phosphodiesterases and cellular levels of adenosine 3' :5'-monophosphate and guanosine 3' :5'-monophosphate and guanosine 3' :5'-monophosphate in relation to the obese syndrome is considered.
...
PMID:Adaptive responses of enzymes of carbohydrate and lipid metabolism to dietary alteration in genetically obese Zucker rats (fa/fa). 71 Mar 95

1. The metabolic response of livers to perfusion with ethanol with and without avenaciolide, has been followed by measuring the perfusate levels of glucose, lactate, pyruvate, beta-hydroxybutyrate, ethanol, amino acids, urea and lipid. 2. Analysis of the perfused livers showed changes in the activities of some of the key enzymes of glycolysis, gluconeogenesis and lipogenesis. Ethanol perfusion decreased the levels of phosphofructokinase, glucokinase and cytosolic isocitrate dehydrogenase, while avenaciolide lowered pyruvate carboxylase and phosphoenolpyruvate carboxykinase as well as glucokinase. Isocitrate dehydrogenase and phosphofructokinase were unchanged, but the ionophore increased the level of fructose-1,6-diphosphatase. Ethanol plus avenaciolide showed the same pattern as ethanol alone, together with the decrease in phosphoenolpyruvate carboxykinase found with avenaciolide. 3. Neither ethanol nor avenaciolide had any effect on kexokinase, pyruvate kinase or acetyl-CoA carboxylase. There were small changes in glucose-6-phosphatase and malic enzyme, and a tendency for citrate lyase levels to decline in avenaciolide perfusions.
...
PMID:The actions of avenaciolide and ethanol on glucose metabolism and on related enzyme activities in the isolated perfused rat liver. 94 10

Levels of mRNA for glucokinase, L-pyruvate kinase, fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxykinase were analysed during liver regeneration. Levels of mRNA for glycolytic enzymes (glucokinase and L-pyruvate kinase) decreased rapidly after partial hepatectomy. Glucokinase mRNA increased at 16-24 h, returning to normal values after this time. L-pyruvate kinase mRNA recovered control levels at 168 h. In contrast, phosphoenolpyruvate carboxykinase mRNA increased rapidly after liver resection and remained high during the regenerative process. However, the levels of fructose-1,6-bisphosphatase mRNA were not modified significantly. These results correlate with the reported increased rate of gluconeogenesis and changes in enzyme levels after partial hepatectomy. The effect of stress on the mRNA levels was also studied. All enzymes showed variations in their mRNA levels after the surgical stress. In general, the differences were more pronounced in regenerating liver than in sham-operated animals, being practically normalized at 24 h.
...
PMID:Gene expression of regulatory enzymes of glycolysis/gluconeogenesis in regenerating rat liver. 132 24

Twenty-four male (12 obese and 12 lean) and 21 female (11 obese and 10 lean) SHR/N-cp rats were fed a diet containing either 54% sucrose or starch for periods of 3-4 months. Rats were killed after a 14-16 h fast and liver enzyme activities were determined in both sex groups. Liver glucose-6-phosphatase (G6Pase), fructose 1,6-bisphosphatase (FBPase), phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), malic enzyme (ME), phosphofructokinase (PFK), glucokinase (GK), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels (per total liver capacity) were significantly affected by phenotype (obese > lean). Arginase and ornithine transcarbamylase levels were analysed only in male rats and were found to be elevated in obese rats as compared to lean littermates. Some of the above changes in enzyme levels were exaggerated by sucrose feeding but not the changes in FBPase, PEPCK, ME and GK (in both sexes) plus AST, arginase and arginine synthase activities in male rats and ALT levels in female rats. Results from SHR/N-cp rats published in this paper were compared to results obtained from LA/N-cp rats published previously. Comparison of the non-diabetic obese LA/N-cp with the diabetic obese SHR/N-cp male shows a greater excess in lipogenic capacity of the liver in the LA/N-cp male rat. The SHR/N-cp obese female also shows a greater liver lipogenic capacity as compared with the obese male SHR/N-cp rat. The results suggest that an adaptation of excessive lipogenesis in the liver of obese rats may be an anti-diabetogenic adaptation resulting in increased glucose conversion to lipids, thus reducing blood glucose levels.
...
PMID:Adaptation in enzyme (metabolic) pathways to obesity, carbohydrate diet and to the occurrence of NIDDM in male and female SHR/N-cp rats. 133 Sep 56

Short- and long-term regulation of hepatic carbohydrate metabolism by insulin-like growth factor II was studied in primary cultures of adult rat hepatocytes and compared to the metabolic potency of insulin. Insulin-like growth factor II stimulated glycogen synthesis from [14C]glucose, uptake of [3H]aminoisobutyric acid and [14C]lactate formation from [14C]glucose up to three-fold. Basal glycogenolysis was inhibited to about 10%, and glucagon-activated glycogenolysis was blocked completely. The enzymatic activity of glucokinase and pyruvate kinase was induced two-fold, the glucagon-dependent induction of phosphoenolpyruvate carboxykinase was antagonized. Compared to insulin, half-maximal responses required up to 50 times higher insulin-like growth factor II concentrations ranging from 10-20 nmol/l. A similar difference was observed for binding affinity of insulin-like growth factor II to the insulin receptor. The interaction with the insulin-like growth factor II/mannose 6-phosphate (IGF-II/Man-6-P) receptor was examined by studying 125I-insulin-like growth factor II binding and uptake of lysosomal enzymes. The affinity of insulin-like growth factor II to the IGF-II/Man-6-P receptor was considerably higher than for the insulin receptor. Antibodies against the IGF-II/Man-6-P receptor did not affect metabolic responses to insulin-like growth factor II, while binding to its receptor and the receptor-mediated endocytosis of arylsulphatase A were strongly inhibited. Thus, in adult rat liver insulin-like growth factor II appeared to exert metabolic actions not via interaction with its own receptor but through low affinity binding to hepatic insulin receptors.
...
PMID:Metabolic actions of insulin-like growth factor II in cultured adult rat hepatocytes are not mediated through the insulin-like growth factor II receptor. 134 10

GLUT-2, glucokinase (GK) and phosphoenolpyruvate carboxykinase (PEPCK) mRNA expression was studied in the liver of chronically catheterized diabetic rats during the 3 days after an intravenous injection of 65 mg of streptozotocin (STZ)/kg. At 6 h after the STZ injection, portal plasma insulin levels were 270 +/- 32 mu-units/ml and blood glucose was 1.4 +/- 0.4 mmol/l, owing to pancreatic beta-cell destruction. GLUT-2 and PEPCK mRNA concentrations were rapidly and dramatically decreased (> 90%), whereas GK mRNA was increased. After 30 h, plasma insulin concentrations were lower than 5 mu-units/ml and blood glucose was > 20 mmol/l. GLUT-2 and PEPCK mRNA concentrations increased 2-fold and GK mRNA disappeared progressively. In order to assess the relative roles of hyperglycaemia and insulinopenia, blood glucose was clamped at 6.4 +/- 0.5 mmol/l from 18 to 72 h after STZ injection by phlorizin infusion (0.5-2 g/day per kg) or at 6.6 +/- 0.3 mmol/l from 18 to 48 h after STZ injection by insulin infusion (0.25 unit/min per kg). GLUT-2 mRNA concentrations were 50% lower in phlorizin-infused than in untreated diabetic rats. The low levels of GK mRNA and the high levels of PEPCK mRNA were unaffected by normalization of hyperglycaemia in phlorizin-infused diabetic rats. In insulin-infused rats (portal plasma insulin levels of 40 mu-units/ml) GLUT-2 mRNA levels were 25% of those in untreated diabetic rats, and they increased rapidly 6 h after insulin infusion was stopped. Liver GLUT-2 protein concentration showed similar changes in response to STZ injection and to phlorizin or insulin treatment, but after a delay of several hours. From this work we conclude that GLUT-2 gene expression is dramatically and rapidly (< 6 h) decreased by portal hyperinsulinaemia and increased by hyperglycaemia.
...
PMID:Evidence that GLUT-2 mRNA and protein concentrations are decreased by hyperinsulinaemia and increased by hyperglycaemia in liver of diabetic rats. 146 68


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

---