Renal enzymes during experimental diabetes mellitus in the rat. Role of insulin, carbohydrate metabolism, and ketoacidosis

1984 ◽  
Vol 62 (1) ◽  
pp. 70-75 ◽  
Author(s):  
Guy Lemieux ◽  
Manuel Rengel Aranda ◽  
Pierrette Fournel ◽  
Christiane Lemieux
Keyword(s):  
Lactate Dehydrogenase ◽  
Glutamine Synthetase ◽  
Glutamate Dehydrogenase ◽  
Malate Dehydrogenase ◽  
Ammonium Chloride ◽  
Malic Enzyme ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Diabetic Rats ◽  
Additional Role

The activities of various ammoniagcnic, gluconeogenic, and glycolytic enzymes were measured in the renal cortex and also in the liver of rats made diabetic with streptozotocin. Five groups of animals were studied: normal, normoglycemic diabetic (insulin therapy), hyperglycemic, ketoacidotic, and ammonium chloride treated rats. Glutaminase I, glutamate dehydrogenase, glutamine synthetase, phosphoenolpyruvate carboxykinase (PEPCK), hexokinase, phosphofructokinase, fructose-1,6-diphos-phatase, malate dehydrogenase, malic enzyme, and lactate dehydrogenase were measured. Renal glutaminase I activity rose during ketoacidosis and ammonium chloride acidosis. Glutamate dehydrogenase in the kidney rose only in ammonium chloride treated animals. Glutamine synthetase showed no particular variation. PEPCK rose in diabetic hyperglycemic animals and more so during ketoacidosis and ammonium chloride acidosis. It also rose in the liver of the diabetic animals. Hexokinase activity in the kidney rose in diabetic insulin-treated normoglycemic rats and also during ketoacidosis. The same pattern was observed in the liver of these diabetic rats. Renal and hepatic phosphofructokinase activities were elevated in all groups of experimental animals. Fructose-1,6-diphosphatase and malate dehydrogenase did not vary significantly in the kidney and the liver. Malic enzyme was lower in the kidney and liver of the hyperglycemic diabetic animals and also in the liver of the ketoacidotic rats. Lactate dehydrogenase fell slightly in the liver of diabetic hyperglycemic and NH4Cl acidotic animals. The present study indicates that glutaminase I is associated with the first step of increased renal ammoniagenesis during ketoacidosis. PEPCK activity is influenced both by hyperglycemia and ketoacidosis, acidosis playing an additional role. Insulin appears to prevent renal gluconeogenesis and to favour glycolysis. The latter would seem to remain operative in hyperglycemic and ketoacidotic diabetic animals.

Respiration and carbohydrate energy metabolism of the lung-dwelling parasite Rhabdias bufonis (Nematoda: Rhabdiasoidea)

Parasitology ◽  
1978 ◽  
Vol 76 (1) ◽  
pp. 21-27 ◽  
Author(s):  
A. O. Anya ◽  
G. M. Umezurike
Keyword(s):  
Lactate Dehydrogenase ◽  
Energy Metabolism ◽  
Malate Dehydrogenase ◽  
Malic Enzyme ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Weight Basis ◽  
Fresh Weight ◽  
Fresh Weight Basis ◽  
Alternative Pathways

SummaryAn investigation of the carbohydrate energy metabolism of Rhabdias bufonis, the lung-dwelling nematode parasite of the African toad, Bufo regularis, indicates that the nematode stores very little glycogen (0·137 ± 0·003% on a fresh weight basis) but does utilize oxygen in vitro. The intracellular distribution and high levels of activity observed for the enzymes phosphoenolpyruvate carboxykinase, pyruvate kinase, lactate dehydrogenase, malate dehydrogenase, malic enzyme and fumarate reductase suggest two alternative pathways of carbohydrate energy metabolism.

scholarly journals First Characterization of an Archaeal GTP-Dependent Phosphoenolpyruvate Carboxykinase from the Hyperthermophilic Archaeon Thermococcus kodakaraensis KOD1

2004 ◽  
Vol 186 (14) ◽  
pp. 4620-4627 ◽  
Author(s):  
Wakao Fukuda ◽  
Toshiaki Fukui ◽  
Haruyuki Atomi ◽  
Tadayuki Imanaka
Keyword(s):  
Binding Sites ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Cation Binding ◽  
Activity Levels ◽  
Binding Region ◽  
Hyperthermophilic Archaeon ◽  
Dependent Activity ◽  
Additional Role

ABSTRACT Phosphoenolpyruvate carboxykinase (PCK), which catalyzes the nucleotide-dependent, reversible decarboxylation of oxaloacetate to yield phosphoenolpyruvate and CO2, is one of the important enzymes in the interconversion between C3 and C4 metabolites. This study focused on the first characterization of the enzymatic properties and expression profile of an archaeal PCK from the hyperthermophilic archaeon Thermococcus kodakaraensis (Pck Tk ). Pck Tk showed 30 to 35% identities to GTP-dependent PCKs from mammals and bacteria but was located in a branch distinct from that of the classical enzymes in the phylogenetic tree, together with other archaeal homologs from Pyrococcus and Sulfolobus spp. Several catalytically important regions and residues, found in all known PCKs irrespective of their nucleotide specificities, were conserved in Pck Tk . However, the predicted GTP-binding region was unique compared to those in other GTP-dependent PCKs. The recombinant Pck Tk actually exhibited GTP-dependent activity and was suggested to possess dual cation-binding sites specific for Mn2+ and Mg2+. The enzyme preferred phosphoenolpyruvate formation from oxaloacetate, since the Km value for oxaloacetate was much lower than that for phosphoenolpyruvate. The transcription and activity levels in T. kodakaraensis were higher under gluconeogenic conditions than under glycolytic conditions. These results agreed with the role of Pck Tk in providing phosphoenolpyruvate from oxaloacetate as the first step of gluconeogenesis in this hyperthermophilic archaeon. Additionally, under gluconeogenic conditions, we observed higher expression levels of Pck Tk on pyruvate than on amino acids, implying that it plays an additional role in the recycling of excess phosphoenolpyruvate produced from pyruvate, replacing the function of the anaplerotic phosphoenolpyruvate carboxylase that is missing from this archaeon.

scholarly journals Role of the complex upstream region of the GDH2 gene in nitrogen regulation of the NAD-linked glutamate dehydrogenase in Saccharomyces cerevisiae.

1991 ◽  
Vol 11 (12) ◽  
pp. 6229-6247 ◽  
Author(s):  
S M Miller ◽  
B Magasanik
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Glutamine Synthetase ◽  
Nitrogen Source ◽  
Glutamate Dehydrogenase ◽  
Regulatory System ◽  
Sole Source ◽  
Lacz Fusion ◽  
Upstream Region ◽  
In Cells

We analyzed the upstream region of the GDH2 gene, which encodes the NAD-linked glutamate dehydrogenase in Saccharomyces cerevisiae, for elements important for the regulation of the gene by the nitrogen source. The levels of this enzyme are high in cells grown with glutamate as the sole source of nitrogen and low in cells grown with glutamine or ammonium. We found that this regulation occurs at the level of transcription and that a total of six sites are required to cause a CYC1-lacZ fusion to the GDH2 gene to be regulated in the same manner as the NAD-linked glutamate dehydrogenase. Two sites behaved as upstream activation sites (UASs). The remaining four sites were found to block the effects of the two UASs in such a way that the GDH2-CYC1-lacZ fusion was not expressed unless the cells containing it were grown under conditions favorable for the activity of both UASs. This complex regulatory system appears to account for the fact that GDH2 expression is exquisitely sensitive to glutamine, whereas the expression of GLN1, coding for glutamine synthetase, is not nearly as sensitive.

The green hydra symbiosis and ammonium. I. The role of the host in ammonium assimilation and its possible regulatory significance

1986 ◽  
Vol 229 (1256) ◽  
pp. 299-314 ◽  
Keyword(s):  
Glutamine Synthetase ◽  
Glutamate Dehydrogenase ◽  
Ammonium Assimilation ◽  
Nitrogen Status ◽  
Continuous Darkness ◽  
Methionine Sulphoximine ◽  
Vacuolar Ph ◽  
Regulatory Significance

Evidence for ammonium assimilation by host and symbiont in algal─invertebrate symbioses is summarized and critically evaluated. The host from all strains of hydra studied possessed glutamine synthetase (GS) and glutamate dehydrogenase (GDH) activities. The host from associations with high maltose releasing algae (E/E, E /3N8) had high GS and low GDH activities, whereas aposymbiotic animals (EALB) and the association with a low maltose releasing alga (E/NC) had low GS and high GDH activities. The observation that symbiotic animals do not release ammonium in the light, whereas aposymbiotic animals release substantial amounts, may be explicable on the basis of variation in the ability of the host to assimilate ammonium. Thus, the photosynthetic inhibitor DCMU had no effect on ammonium release by symbiotic animals, with the possible exception of E/NC. Methionine sulphoximine (MSO) completely inhibited GS activity from EALB both in vitro and in vivo . In the presence of MSO, ammonium release was enhanced in both EALB and E/E. In continuous darkness, an increase in ammonium released by symbiotic animals (E/E) was correlated with a decrease in host GS activity. It is suggested that the evidence is consistent with host and not symbiont assimilation of ammonium. A model of symbiont regulation is proposed based on regulation of ammonium supply as a means of controlling both perialgal vacuolar pH and symbiont nitrogen status.

scholarly journals Role of malate dehydrogenase in facilitating lactate dehydrogenase to support the glycolysis pathway in tumors

2017 ◽  
Vol 6 (4) ◽  
pp. 463-467 ◽  
Author(s):  
Siavash Mansouri ◽  
Ali Shahriari ◽  
Hadi Kalantar ◽  
Taraneh Moini Zanjani ◽  
Mojtaba Haghi Karamallah
Keyword(s):  
Lactate Dehydrogenase ◽  
Malate Dehydrogenase ◽  
Glycolysis Pathway

NADP-linked dehydrogenases in secreted milk

1985 ◽  
Vol 52 (4) ◽  
pp. 501-506 ◽  
Author(s):  
Murray R. Grigor ◽  
Peter E. Hartmann
Keyword(s):  
Mammary Gland ◽  
Lactate Dehydrogenase ◽  
Malate Dehydrogenase ◽  
Isocitrate Dehydrogenase ◽  
Malic Enzyme ◽  
Prolonged Storage ◽  
Phosphogluconate Dehydrogenase ◽  
The Absolute ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Accurate Reflection

SUMMARYThe activities of glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase, malic enzyme, lactate dehydrogenase and malate dehydrogenase have been determined in secreted milk from sows, rats and rabbits. Within each species, although there was considerable variation in the absolute activities of these enzymes, the relative activities were similar to those observed for, or previously published for mammary homogenates. The only exception was milk glucose 6-phosphate dehydrogenase which tended to lose activity upon prolonged storage in the mammary gland. These results suggest that the pattern of milk enzymes can be an accurate reflection of that occurring in the mammary gland.

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