scholarly journals The biochemistry of fatty liver and kidney syndrome. Biotin-mediated restoration of hepatic gluconeogenesis in vitro and its relationship to pyruvate carboxylase activity

1976 ◽  
Vol 156 (1) ◽  
pp. 167-173 ◽  
Author(s):  
D W Bannister
Keyword(s):  
Fatty Liver ◽  
Nutrient Medium ◽  
Pyruvate Carboxylase ◽  
Control Valve ◽  
Protein Synthesis Inhibitors ◽  
Hepatic Gluconeogenesis ◽  
Carboxylase Activity ◽  
Liver And Kidney ◽  
Rate Limiting

Liver slices from chicks affected by the fatty liver and kidney syndrome display an extremely low extent of hepatic gluconeogenesis which is associated with decreased activities of certain rate-limiting gluconeogenic enzymes. Pyruvate carboxylase activity is particularly severely affected, being less than 4% of control values. Incubation of affected slices in a biotin-containing nutrient medium restores both gluconeogenesis and pyruvate carboxylase actiivity (the latter to approx. 35% of the control valve). Activities of the other enzymes studied were not greatly affected by this treatment. Restoration of gluconeogenesis did not occur if biotin was excluded from the nutrient medium, nor was it prevented by protein-synthesis inhibitors. It is concluded that the syndrome involves the lack of available biotin in the liver rather than suppression of apocarboxylase synthesis.

scholarly journals Metabolic changes associated with the occurrence of fatty liver and kidney syndrome in chicks

1978 ◽  
Vol 40 (2) ◽  
pp. 221-234 ◽  
Author(s):  
C. C. Whitehead ◽  
D. W Bannister ◽  
Maureen E. Cleland
Keyword(s):  
Lactate Dehydrogenase ◽  
Fatty Liver ◽  
Pyruvate Carboxylase ◽  
Liver Weight ◽  
High Plasma ◽  
Broiler Chicks ◽  
Plasma Lactate ◽  
Carboxylase Activity ◽  
Lactate Dehydrogenase Activity ◽  
Liver And Kidney

1. The changes in a number of metabolic measurements brought about by low-biotin diets associated with high and low incidences of fatty liver and kidney syndrome (FLKS) were studied in healthy 4-week-old broiler chicks.2. Liver pyruvate carboxylase (pyruvate: CO2 ligase (ADP); EC 6.4.1.1) activity was low in birds fed on a diet causing a high incidence of FLKS but the addition of fat or protein to this diet, to decrease the incidence of FLKS, increased enzyme activity.3. Liver weights, blood lactate concentrations, plasma lactate dehydrogenase (l-lactate:NAD oxidoreductase; EC 1.1.1.27) activities and values for C16:1:C18:0 fatty acid in liver, adipose tissue and plasma triglyceride were highest in birds fed on the high-FLKS diet and all measurements were negatively correlated with pyruvate carboxylase activity.4. Birds with high plasma lactate dehydrogenase activity or triglyceride C16:1:C18:0 values were the most likely to develop FLKS when fasted.5. There was no evidence that increased liver weight was associated with increased activities of certain other liver enzymes.6. It is concluded that FLKS occurs in birds with little or no hepatic gluconeogenic capacity via pyruvate carboxylase as a result of a dietary insufficiency of biotin but that the initiation of the syndrome is probably associated with the inhibition of other pathways of gluconeogenesis.

The influence of pH on kinetic parameters of coleoptile phosphoenolpyruvate carboxylase. Relationship to auxin-stimulated dark fixation

1979 ◽  
Vol 57 (5) ◽  
pp. 543-547 ◽  
Author(s):  
Ceredwyn Smith ◽  
Ahmed Doo ◽  
Alan W. Bown
Keyword(s):  
Binding Affinity ◽  
Catalytic Efficiency ◽  
Enzymic Activity ◽  
Carboxylase Activity ◽  
Pep Carboxylase ◽  
Ph Values ◽  
Dark Fixation ◽  
Rate Limiting ◽  
Cytosol Ph

In vitro phosphoenolpyruvate (PEP) carboxylase activity from Avena coleoptile tissue was investigated over a range of pH values which include cytosol pH values. Increasing the pH from 7.0 to 7.5 increased optimal PEP carboxylase activity (Vmax) by over 100%. In the presence of rate-limiting 0.07 mM PEP, noncompetitive inhibition by 0.1 mM malate decreased from 80% at pH 7.1 to 50% at pH 7.5. The Km for PEP was not influenced by malate, but as the pH was increased from 7.1 to 7.5, the Km decreased from 0.16 to 0.08 mM. Over the same pH rise, the KI for malate inhibition increased from 0.04 mM to 0.09 mM. Fusicoccin had no detectable influence on enzymic activity. These results are discussed in relation to the stimulation of H+ excretion and dark CO2 fixation by indoleacetic acid and fusicoccin. The data indicate that any increase in cytosol pH, resulting from H+ excretion, would stimulate PEP carboxylase activity by promoting catalytic efficiency and binding affinity for PEP and by reducing the binding affinity for the inhibitor malate.

Activities of the enzymes of hepatic gluconeogenesis in periparturient dairy cows with induced fatty liver

2004 ◽  
Vol 71 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Absolom Murondoti ◽  
Ruurd Jorritsma ◽  
Anton C Beynen ◽  
Theo Wensing ◽  
Math JH Geelen
Keyword(s):  
Fatty Liver ◽  
Dairy Cows ◽  
Pyruvate Carboxylase ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Post Partum ◽  
Sampling Period ◽  
Negative Energy ◽  
Hepatic Gluconeogenesis ◽  
Gluconeogenic Enzymes ◽  
Blood Glucose Concentrations

The objective was to measure the activities of all the enzymes essential for hepatic gluconeogenesis in dairy cows with induced fatty liver. We aimed to induce severe fatty liver in ten experimental cows by overfeeding them during the dry period while seven control cows were maintained on a restricted diet. To induce a marked negative energy balance, the experimental cows were deprived of feed for 8 h immediately after parturition. In addition, the experimental cows were given a restricted amount of diet during the first 5 d of lactation. Liver samples were collected 1 week before and 1, 2 and 4 weeks after parturition. Before parturition, liver triacylglycerol concentrations did not differ between the two groups. After parturition, the experimental cows developed marked fatty liver as indicated by a higher level of triacylglycerols in the liver compared with the control cows.Before parturition, all gluconeogenic enzymes in the liver were lower in experimental cows than in control cows. Phosphoenolpyruvate carboxykinase, pyruvate carboxylase and propionyl-CoA carboxylase were significantly lower and fructose 1,6-bisphosphatase and glucose 6-phosphatase tended to be lower in the experimental cows. The activities of two crucial enzymes for gluconeogenesis in ruminants, i.e., phosphoenolpyruvate carboxykinase and propionyl-CoA carboxylase, remained low throughout the sampling period post partum. Activities of pyruvate carboxylase and glucose 6-phosphatase in the experimental cows post partum were upgraded to values similar to those of the control cows. The results showed that the capacity for hepatic gluconeogenesis before parturition was lower in cows with induced fatty liver than in control cows. After parturition, the low activities of crucial gluconeogenic enzymes indicated insufficient production of glucose. It is suggested that the low gluconeogenic capacity leads successively to low blood glucose concentrations, low insulin levels and high rates of mobilization of fatty acid, causing severe hepatic lipidosis.

scholarly journals The activities and intracellular distribution of nicotinamide-adenine dinucleotide phosphate-malate dehydrogenase, phosphoenolpyruvate carboxykinase and pyruvate carboxylase in rat, guinea-pig and rabbit tissues

1975 ◽  
Vol 146 (2) ◽  
pp. 329-332 ◽  
Author(s):  
D E Saggerson ◽  
C J Evans
Keyword(s):  
Adipose Tissue ◽  
Guinea Pig ◽  
Malate Dehydrogenase ◽  
Pyruvate Carboxylase ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Intracellular Distribution ◽  
Kidney Cortex ◽  
Carboxylase Activity ◽  
Liver And Kidney

1. Measurements are presented of the activity and intracellular distribution of phosphoenolypruvate carboxykinase, pyruvate carboxylase and NADP-malate dehydrogenase in rat, guinea-pig and rabbit liver and kidney cortex, together with previously obtained measurements of these enzymes in adipose tissue. 2. In all three tissues pyruvate carboxylase activity was greatest in the rat and lowest in the rabbit. 3. Guinea pig and rabbit were very similar to each other with respect to the extramitochondrial-mitochondrial distribution of phosphoenolpyruvate carboxykinase in all three tissues. 4. NADP-malate dehydrogenase was present in all three tissues in the rat, present in kidney cortex and adipose tissue in the guinea pig and absent from all tissues examines in the rabbit.

Decreased aminotransferase activity of serum and various tissues in the rat after cefazolin treatment.

1979 ◽  
Vol 25 (7) ◽  
pp. 1263-1266 ◽  
Author(s):  
M S Dhami ◽  
R Drangova ◽  
R Farkas ◽  
T Balazs ◽  
G Feuer
Keyword(s):  
Enzyme Activity ◽  
Pyruvate Carboxylase ◽  
Aminotransferase Activity ◽  
Liver And Kidney ◽  
Mixed Function Oxidase System ◽  
The Brain ◽  
Microsomal Mixed Function Oxidase ◽  
Alanine Aminotransferase Activity

Abstract Treatment of rats with cefazolin in vivo significantly suppressed activity of alanine and aspartate aminotransferases in serum and in the liver, brain, kidney, and heart. Simultaneous administration of pyridoxal further reduced enzyme activity except in the liver, where there was no change. Pyridoxal 5'-phosphate partly reversed the decreased enzyme activity in the serum, liver, and kidney, but did not return it to the amount observed in the control animals; enzyme activity remained suppressed in the brain and heart. The effect of cefazolin was dose related, but there was no sex-related difference. In contrast to its action on am-notransferase activity, cefazolin elicited no effect on alkaline phosphatase (pyridoxal-5'-phosphate hydrolase) in serum or on pyruvate carboxylase in the liver, heart, and kidney. Cefazolin exposed to the hepatic microsomal mixed-function oxidase system in vitro was partly converted into metabolites that inhibited serum alanine aminotransferase activity in vitro. The latter inhibition was reversed by the addition of pyridoxal 5'-phosphate.

scholarly journals Fatty Liver and Kidney Syndrome in Chicks II. Biochemical Role of Biotin

1976 ◽  
Vol 29 (6) ◽  
pp. 429 ◽  
Author(s):  
RL Hood ◽  
A RJohnson ◽  
AC Fogerty ◽  
Judith A Pearson
Keyword(s):  
Fatty Liver ◽  
Pyruvate Carboxylase ◽  
Acetyl Coa Carboxylase ◽  
Defence Mechanisms ◽  
Acetyl Coa ◽  
Liver Size ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Liver And Kidney

The role of biotin-dependent enzymes in the fatty liver and kidney syndrome of young chicks was studied. Under conditions of a marginal deficiency of dietary biotin, the level of biotin in the liver has differing effects on the activities of two biotin-dependent enzymes, pyruvate carboxylase and acetyl-CoA carboxylase. The activity of acetyl-CoA carboxylase is increased, but when the dietary deficiency of biotin produces biotin levels which are below o� 8 p,g/g of liver, the activity of pyruvate carboxylase may be insufficient to completely metabolize pyruvate via gluconeogenesis. There is an increase in liver size and in the activities of enzymes involved in alternate pathways for the removal of pyruvate. Blood lactate accumulates and there is increased synthesis of fatty acids, and an accumulation of palmitoleic acid; these steps are accomplished by increased activities of at least the following enzymes: acetyl-CoA carboxylase, malate dehydrogenase (decarboxylating) (NADP+) and the desaturase enzyme. When the biotin level is below 0�35 p,g/g of liver and the chick is subjected to a stress, physiological defence mechanisms of the chick may be inadequate to maintain homeostasis and they finally collapse, resulting in accumulation of triacylglycerol in the liver and blood; the chick is unable to maintain blood glucose levels and death occurs, often only a few hours after the imposition of the stress.

scholarly journals Potent heme-degrading action of antimony and antimony-containing parasiticidal agents

1981 ◽  
Vol 153 (2) ◽  
pp. 245-256 ◽  
Author(s):  
GS Drummond ◽  
A Kappas
Keyword(s):  
Heme Oxygenase ◽  
Transition Elements ◽  
Potent Inducer ◽  
Heme Degradation ◽  
Liver And Kidney ◽  
Mixed Function Oxidase System ◽  
Rebound Increase ◽  
Rate Limiting ◽  
Dose Dependent

The ability of antimony and antimony-containing parasiticidal agents to enhance the rate of heme degradation in liver and kidney was investigated. Trivalent antimony was shown to be an extremely potent inducer of heme oxygenase, the initial and rate-limiting enzyme in heme degradation, in both organs, whereas the pentavalent form was a weak inducer of this enzyme. The ability of antimony to induce heme oxygenase was dose-dependent, independent of the salt used, and not a result of a direct activation of the enzyme in vitro. Concomitant with heme oxygenase induction by antimony, microsomal heme and cytochrome P-450 contents decreased, the cyto-chrome P-450-dependent mixed function oxidase system was impaired, and δ-ami-nolevulinate synthase (ALAS), the rate-limiting enzyme of heme synthesis, underwent the sequential changes-initial inhibition followed by rebound induction-usually associated with the administration of transition elements such as cobalt. Antimony induction of heme oxygenase however, unlike the enzyme induction elicited by cobalt, was not prevented either by cysteine administered orally or as a cysteine metal complex, or by simultaneous zinc administration. Desferoxamine also did not block heme oxygenase induction by antimony, but this chelator did prevent the rebound increase in ALAS activity associated with antimony or cobalt treatment. Antimony-containing parasiticidal drugs were also potent inducers of heme oxygenase in liver and kidney. The heme degradative action of these drugs may be related in part to the jaundice commonly associated with the prolonged therapeutic use of these agents. The heme-oxygenase-inducing action of antimony-containing parasiticidal drugs is a newly defined biological property of these compounds. The relation between the parasiticidal and the heme-oxygenase-inducing actions of such drugs is unknown. However, certain parasites contain hemoproteins or require heme compounds during their life cycle. It may therefore be useful to explore the possibility that the heme-degrading and the parasiticidal actions of certain metals or metal-containing therapeutic agents are in some way related.

The influence of biotin on viability, pyruvate carboxylase activity and the response to malate concentration in vitro by isolated secondary hair follicles of the Angora goat

1999 ◽  
Vol 1999 ◽  
pp. 158-158
Author(s):  
A.M. Tahmasbi ◽  
H. Galbraith ◽  
J.R. Scaife
Keyword(s):  
Pyruvate Carboxylase ◽  
Krebs Cycle ◽  
Hair Follicles ◽  
Prosthetic Group ◽  
Biotin Deficiency ◽  
Carboxylase Activity ◽  
Poor Growth ◽  
Krebs Cycle Intermediates ◽  
Biotin Supplementation

Biotin is a prosthetic group for a number of enzymes involved in carboxylation reactions. Biotin deficiency has been associated with poor growth of integumental tissues by currently unknown mechanisms. Pyruvate carboxylase is a biotin-dependent enzyme which has an important anaplerotic role in intermediary metabolism, catalysing the formation of oxaloacetate from pyruvate and bicarbonate. It thus provides oxaloacetate for gluconeogenesis and replenishes Krebs cycle intermediates. Biotin deficiency may reduce pyruvate carboxylase activity and so oxaloacetate production. Malate is a Krebs cycle intermediate which can convert to oxaloacetate and reduce demand for oxaloacetate generated by pyruvate carboxylase. The aims of the study were to determine (a) the effect of biotin supplementation of the medium on hair follicle viability and pyruvate carboxylase activity and (b) the response to supplementation of the culture medium with malate.

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