Ammonium Chloride Inhibits Pyruvate Oxidation in Rat Liver Mitochondria: A Possible Cause of Fatty Liver in Reye's Syndrome and Urea Cycle Defects

1994 ◽  
Vol 87 (5) ◽  
pp. 499-503 ◽  
Author(s):  
Vaddanahally T. Maddaiah ◽  
Uday Kumbar
Keyword(s):  
Oxidative Metabolism ◽  
Urea Cycle ◽  
Tricarboxylic Acid Cycle ◽  
Liver Mitochondria ◽  
Fatty Acyl ◽  
Rat Liver Mitochondria ◽  
Acid Oxidation ◽  
Reye's Syndrome ◽  
Acetyl Coa ◽  
Total Oxidation

1. Earlier studies with liver slices showed that inhibition by NH+4 of the oxidation of palmitate to CO2 was greater than total oxidation, whereas salicylate exerted a stronger inhibitory effect on the latter. We have now investigated the effects of NH4Cl and salicylate on ADP-induced O2 consumption by mitochondria (State 3 rate) respiring on pyruvate, and oxidation of [1-14C]- and [2-14C]-pyruvate to14CO2. 2. The rate of State 3 respiration was inhibited and plateaued at 45% with 10 mmol/l NH4Cl. 3. Oxidation of [1-14C]pyruvate was not significantly affected by either NH4Cl or salicylate. Oxidation of [2-14C]pyruvate was strongly inhibited and plateaued at 70% with 1 mmol/1 NH4Cl (IC50 = 0.125 mmol/1). ADP (1 mmol/l) increased the rate of decarboxylation of [2-14C] pyruvate but the extent of NH4Cl inhibition was not affected. Salicylate had a slight activating effect in the absence or presence of NH4Cl. 4. These results indicate that NH4Cl inhibits the oxidative metabolism of acetyl-CoA in the tricarboxylic acid cycle. Therefore, inhibition of fatty acid oxidation to acetyl-CoA as well as its further oxidative metabolism occurring under hyperammonaemia (>0.1 mmol-1.49 mmol/l in Reye's syndrome patients) may be one of the causes of fatty acidaemia. 5. The cumulative inhibitory effects of NH+4 and fatty acyl derivatives on mitochondrial oxidative metabolism and production of ATP, as well as the uncoupling effects of salicylate, may contribute to some of the pathophysiology observed in patients with Reye's syndrome, and enzyme defects of the urea cycle.

Reversal of mitochondrial swelling associated with fatty acid oxidation. II. Effects of cytochrome c and carnitine on contraction of fatty acid swollen mitochondria

1968 ◽  
Vol 46 (9) ◽  
pp. 1151-1160 ◽  
Author(s):  
Misako Nakatani ◽  
W. C. McMurray
Keyword(s):  
Fatty Acid ◽  
Cytochrome C ◽  
Energy Requirement ◽  
Liver Mitochondria ◽  
High Energy ◽  
Fatty Acyl ◽  
Water Soluble ◽  
Rat Liver Mitochondria ◽  
Acid Oxidation ◽  
Swelling Agent

Rat liver mitochondria undergo reversible swelling in the presence of a fatty acyl CoA generating system. Contraction of the swollen mitochondria was observed on the addition of either carnitine or cytochrome c. At low concentrations the two agents acted synergistically. At high concentrations cytochrome c completely replaced the requirement for carnitine.Cytochrome c also promoted the contraction of mitochondria swollen in the presence of fatty acid alone, provided that either ATP or ADP was added to initiate the contraction. The stimulation by cytochrome c was greater in the presence of ADP, and the contraction was more sensitive to respiratory inhibitors or dinitrophenol but was less sensitive to oligomycin than in the presence of ATP. Studies of the metabolism of 14C-labelled palmitate during cytochrome c induced contraction showed that decreases in mitochondrial-bound fatty acid and corresponding increases in water-soluble metabolites coincided with the reversal of swelling. The results indicated that the energy requirement for mitochondrial contraction in the presence of cytochrome c was provided by generation of high-energy intermediates coupled to oxidation of the fatty acid swelling agent.

scholarly journals Hepatic ketogenesis in newborn pigs is limited by low mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase activity

1994 ◽  
Vol 298 (1) ◽  
pp. 207-212 ◽  
Author(s):  
P H Duée ◽  
J P Pégorier ◽  
P A Quant ◽  
C Herbin ◽  
C Kohl ◽  
...  
Keyword(s):  
Rat Liver ◽  
Liver Mitochondria ◽  
Oxidation Products ◽  
Rat Liver Mitochondria ◽  
Acid Oxidation ◽  
Acetyl Coa ◽  
Pig Liver ◽  
Adult Rat ◽  
Malonyl Coa ◽  
Cpt I

In newborn-pig hepatocytes, the rate of oleate oxidation is extremely low, despite a very low malonyl-CoA concentration. By contrast, the sensitivity of carnitine palmitoyltransferase (CPT) I to malonyl-CoA inhibition is high, as suggested by the very low concentration of malonyl-CoA required for 50% inhibition of CPT I (IC50). The rates of oleate oxidation and ketogenesis are respectively 70 and 80% lower in mitochondria isolated from newborn-pig liver than from starved-adult-rat liver mitochondria. Using polarographic measurements, we showed that the oxidation of oleoyl-CoA and palmitoyl-L-carnitine is very low when the acetyl-CoA produced is channelled into the hydroxymethylglutaryl-CoA (HMG-CoA) pathway by addition of malonate. In contrast, the oxidation of the same substrates is high when the acetyl-CoA produced is directed towards the citric acid cycle by addition of malate. We demonstrate that the limitation of ketogenesis in newborn-pig liver is due to a very low amount and activity of mitochondrial HMG-CoA synthase as compared with rat liver mitochondria, and suggest that this could promote the accumulation of acetyl-CoA and/or beta-oxidation products that in turn would decrease the overall rate of fatty acid oxidation in newborn- and adult-pig livers.

scholarly journals Steady-state concentrations of coenzyme A, acetyl-coenzyme A and long-chain fatty acyl-coenzyme A in rat-liver mitochondria oxidizing palmitate

1965 ◽  
Vol 97 (2) ◽  
pp. 587-594 ◽  
Author(s):  
PB Garland ◽  
D Shepherd ◽  
DW Yates
Keyword(s):  
Rat Liver ◽  
Coenzyme A ◽  
Liver Mitochondria ◽  
Fatty Acyl ◽  
Rat Liver Mitochondria ◽  
Beta Oxidation ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Acyl Coenzyme A ◽  
Long Chain

1. Fluorimetric assays are described for CoASH, acetyl-CoA and long-chain fatty acyl-CoA, and are sensitive to at least 50mumumoles of each. 2. Application of these assays to rat-liver mitochondria oxidizing palmitate in the absence and presence of carnitine indicated two pools of intramitochondrial CoA. One pool could be acylated by palmitate and ATP, and the other pool acylated by palmitate with ATP and carnitine, or by palmitoylcarnitine alone. 3. The intramitochondrial content of acetyl-CoA is increased by the oxidation of palmitate both in the absence and presence of l-malate. 4. The conversion of palmitoyl-CoA into acetyl-CoA by beta-oxidation takes place without detectable accumulation of acyl-CoA intermediates.

scholarly journals Intermediates in fatty acid oxidation

1973 ◽  
Vol 132 (1) ◽  
pp. 61-76 ◽  
Author(s):  
H. B. Stewart ◽  
P. K. Tubbs ◽  
K. K. Stanley
Keyword(s):  
Liver Mitochondria ◽  
Fatty Acyl ◽  
Acid Oxidation ◽  
Aqueous Extracts ◽  
Multienzyme Complex ◽  
Acetyl Coa ◽  
Kidney Mitochondria ◽  
Liver And Kidney ◽  
Phenazine Methosulphate ◽  
Derivatives Of

1. Aqueous extracts of acetone-dried liver and kidney mitochondria, supplemented with NAD+, CoA and phenazine methosulphate, efficiently convert fatty-acyl-CoA compounds into acetyl-CoA; the process was followed with an O2 electrode. 2. Label from [1-14C]octanoyl-CoA appears in acetyl-CoA more rapidly than that from [8-14C]octanoyl-CoA. 3. Oxidation of [8-14C]octanoyl-CoA was terminated by addition of neutral ethanolic hydroxylamine and the resulting hydroxamates were separated chromatographically. Hydroxamate derivatives of 3-hydroxyoctanoyl-, hexanoyl-, butyryl- and acetyl-CoA were obtained. 4. These and other observations suggest that oxidation of octanoyl-CoA by extracts involves participation of free intermediates rather than uninterrupted complete degradation of individual molecules to acetyl-CoA by a multienzyme complex. 5. Intact liver mitochondria studied by the hydroxamate technique were also shown to form intermediates during oxidation of labelled octanoates. In addition to octanoylhydroxamate, [8-14C]octanoate gave rise to small amounts of hexanoyl-, butyryl- and 3-hydroxyoctanoyl-hydroxamate. In contrast with extracts, however, where the quantity of intermediates found was a significant fraction of the precursors, mitochondria oxidizing octanoate contained much larger quantities of octanoyl-CoA than of any other intermediate.

scholarly journals The localization of some coenzyme A-dependant enzymes in rat liver mitochondria

1970 ◽  
Vol 119 (3) ◽  
pp. 565-573 ◽  
Author(s):  
B. A. Haddock ◽  
D. W. Yates ◽  
P. B. Garland
Keyword(s):  
Outer Membrane ◽  
Chain Length ◽  
Rat Liver ◽  
Membrane Fraction ◽  
Liver Mitochondria ◽  
Fatty Acyl ◽  
Rat Liver Mitochondria ◽  
Acetyl Coa ◽  
Inner Membrane ◽  
The Matrix

1. CoA, acetyl-CoA, l-carnitine and acetyl-l-carnitine when added to rat liver mitochondria equilibrate with approximately two-thirds of the total intramitochondrial water. The mitochondrial space calculated to be freely permeable to these solutes was identical with that obtained for sucrose. 2. Acetyl-CoA is rapidly deacylated by rat liver mitochondria at 0°C, and special precautions are required to measure its mitochondrial permeation. 3. Rat liver mitochondria were separated into fractions that correspond to the inner membrane, the outer membrane, and the soluble proteins of the matrix and intermembrane compartment. Soluble enzymes considered to be located in the matrix were citrate synthase (EC 4.1.3.7), palmitoyl-CoA dehydrogenase (EC 1.3.2.2), electron-transferring flavoprotein, medium-chain-length ATP-specific fatty acyl-CoA synthetase (EC 6.2.1.2), l-3-hydroxybutyryl-CoA dehydrogenase (EC 1.1.1.35) and 3-keto-acyl-CoA thiolase (EC 2.3.1.16). Carnitine palmitoyltransferase (EC 2.3.1.–) is largely associated with the inner-membrane fraction. A long-chain-length ATP-specific fatty acyl-CoA synthetase (EC 6.2.1.3) is associated with the outer-membrane fraction.

Expression Profile of Acetyl CoA Carboxylase Beta (ACACB) Gene during the Pre and Post-hatch Period in Chicken

2021 ◽  
Author(s):  
Ch. Shiva Prasad ◽  
R. Vinoo ◽  
R.N. Chatterjee ◽  
M. Muralidhar ◽  
D. Narendranath ◽  
...  
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Expression Pattern ◽  
Fatty Acyl ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Layer Chicken ◽  
Differential Expression Pattern ◽  
Long Chain

Background: Acetyl-CoA Carboxylase Beta (ACACB) plays a key role in fatty acid oxidation and was known to be involved in production of very-long-chain fatty acid and other compounds needed for proper development. This gene is mainly expressed in the tissues of heart, muscle, liver and colon. It chiefly involved in the production of malonyl-coA, a potent inhibitor of carnitine palmitoyl transferase I (CPT-I) enzyme needed in transport of long-chain fatty acyl-coAs to the mitochondria for β-oxidation.Methods: The present study was conducted to explore the expression pattern of the ACACB gene in breast muscle tissue during pre-hatch embryonic day (ED) 5th to 18th and post-hatch (18th, 22nd and 40th week of age) periods of White leghorn (IWI line) by using Quantitative real-time PCR (qPCR). Then, fold change of ACACB gene expression was calculated.Result: Our study showed that the ACACB gene expression was down-regulated during embryonic stages from ED6 to ED18. The gene expression was also down-regulated during adult stages i.e. on 22nd and 40th week of age. This result indicated that the initial expression of the ACACB gene is required for embryo development and during adult periods, low gene expression leads to the less fat deposition in muscle of layer chicken. Finally, it can be concluded that there was a differential expression pattern of the ACACB gene during the pre-hatch embryonic and post-hatch adult periods to mitigate varied requirements of lipids during different physiological stages in layer chicken.

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