scholarly journals Catabolism of 2-methyloctanoic acid and 3β-hydroxycholest-5-en-26-oic acid

1966 ◽  
Vol 101 (3) ◽  
pp. 632-635 ◽  
Author(s):  
PDG Dean ◽  
MW Whitehouse
Keyword(s):  
Carbon Dioxide ◽  
Palmitic Acid ◽  
Propionic Acid ◽  
Octanoic Acid ◽  
Mammalian Species ◽  
Liver Mitochondria ◽  
Acid Oxidation ◽  
Kidney Mitochondria ◽  
Mammalian Liver ◽  
Brown Fat Mitochondria

1. 2-Methyl[1-(14)C]octanoic acid was synthesized from 2-bromo-octane and (14)CO(2). 2. 2-Methyl[1-(14)C]octanoic acid was readily oxidized to propionic acid and carbon dioxide by mitochondrial preparations from liver, less readily oxidized by adrenal and kidney (mitochondria), and only poorly oxidized by heart, spleen and brown fat (mitochondria). 3. 3beta-Hydroxy[26-(14)C]cholest-5-en-26-oic acid was rapidly oxidized by mammalian-liver mitochondria to propionic acid and carbon dioxide. Caiman-liver and toad-liver mitochondria also oxidized this steroid acid. 4. The oxidation of propionic acid, octanoic acid and palmitic acid by mitochondrial preparations from these various tissues was also studied. 5. Added carnitine did not stimulate 2-methyloctanoic acid oxidation and feebly stimulated 3beta-hydroxycholest-5-en-26-oic acid oxidation. 6. The significance of these results is discussed in relation to sterol catabolism in mammals and non-mammalian species.

scholarly journals Inhibition of oxidative metabolism by propionic acid and its reversal by carnitine in isolated rat hepatocytes

1986 ◽  
Vol 236 (1) ◽  
pp. 131-136 ◽  
Author(s):  
E P Brass ◽  
P V Fennessey ◽  
L V Miller
Keyword(s):  
Palmitic Acid ◽  
Propionic Acid ◽  
Oxidative Metabolism ◽  
Rat Hepatocytes ◽  
Inhibitory Effect ◽  
Acid Oxidation ◽  
Isolated Rat Hepatocytes ◽  
Pyruvate Oxidation ◽  
Metabolic Basis ◽  
Isolated Rat

The present study was designed to study the interaction of propionic acid and carnitine on oxidative metabolism by isolated rat hepatocytes. Propionic acid (10 mM) inhibited hepatocyte oxidation of [1-14C]-pyruvate (10 mM) by 60%. This inhibition was not the result of substrate competition, as butyric acid had minimal effects on pyruvate oxidation. Carnitine had a small inhibitory effect on pyruvate oxidation in the hepatocyte system (210 +/- 19 and 184 +/- 18 nmol of pyruvate/60 min per mg of protein in the absence and presence of 10 mM-carnitine respectively; means +/- S.E.M., n = 10). However, in the presence of propionic acid (10 mM), carnitine (10 mM) increased the rate of pyruvate oxidation by 19%. Under conditions where carnitine partially reversed the inhibitory effect of propionic acid on pyruvate oxidation, formation of propionylcarnitine was documented by using fast-atom-bombardment mass spectroscopy. Propionic acid also inhibited oxidation of [1-14C]palmitic acid (0.8 mM) by hepatocytes isolated from fed rats. The degree of inhibition caused by propionic acid was decreased in the presence of 10 mM-carnitine (41% inhibition in the absence of carnitine, 22% inhibition in the presence of carnitine). Propionic acid did not inhibit [1-14C]palmitic acid oxidation by hepatocytes isolated from 48 h-starved rats. These results demonstrate that propionic acid interferes with oxidative metabolism in intact hepatocytes. Carnitine partially reverses the inhibition of pyruvate and palmitic acid oxidation by propionic acid, and this reversal is associated with increased propionylcarnitine formation. The present study provides a metabolic basis for the efficacy of carnitine in patients with abnormal organic acid accumulation, and the observation that such patients appear to have increased carnitine requirements (‘carnitine insufficiency’).

Effects of glucose on fatty acid oxidation by diaphragms from normal and alloxan-diabetic fed and starved rats

1960 ◽  
Vol 198 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Irving B. Fritz ◽  
Eli Kaplan
Keyword(s):  
Fatty Acid ◽  
Palmitic Acid ◽  
Fatty Acid Oxidation ◽  
Octanoic Acid ◽  
Diabetic Rats ◽  
Chain Fatty Acid ◽  
Acid Oxidation ◽  
Long Chain Fatty Acid ◽  
Fatty Acid Degradation ◽  
Long Chain

Palmitic acid-1-C14 oxidation by hemidiaphragms was measured in tissues from fed and starved normal and alloxanized rats. Muscle from normal rats starved for 3 days or longer showed an enhanced conversion of added palmitate to C14O2, while fasting for 1 or 2 days had little effect on fatty acid degradation by diaphragms from normal rats. Tissues from fed or starved alloxan diabetic animals had an augmented oxidation of labeled palmitate. The addition of glucose to the medium spared fatty acid oxidation by diaphragms from starved or diabetic rats but did not influence palmitate degradation by tissues from normal fed rats. The presence of insulin increased the glucose sparing action on long-chain fatty acid oxidation but was without effect on palmitate oxidation in the absence of added glucose. The conversion of C14-octanoic acid to C14O2 by muscle was not influenced by previous starvation nor by addition of glucose to the medium. Glucose-U-C14 and glucose-1-C14 conversion to C14O2 and glycogen were essentially the same in diaphragms from fed and starved animals.

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 CARBOXYLATION OF PROPIONIC ACID BY LIVER MITOCHONDRIA

1956 ◽  
Vol 219 (2) ◽  
pp. 943-950 ◽  
Author(s):  
Felix Friedberg ◽  
Julius Adler ◽  
Henry A. Lardy
Keyword(s):  
Propionic Acid ◽  
Liver Mitochondria

scholarly journals miR-21-5p regulates mitochondrial respiration and lipid content in H9C2 cells

2019 ◽  
Vol 316 (3) ◽  
pp. H710-H721 ◽  
Author(s):  
Victoria L. Nasci ◽  
Sandra Chuppa ◽  
Lindsey Griswold ◽  
Kathryn A. Goodreau ◽  
Ranjan K. Dash ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acid ◽  
Palmitic Acid ◽  
Fatty Acid Oxidation ◽  
Lipid Content ◽  
Mitochondrial Respiration ◽  
Acid Oxidation ◽  
H9c2 Cells ◽  
Cellular Lipid ◽  
Transfected Cells

Cardiovascular-related pathologies are the single leading cause of death in patients with chronic kidney disease (CKD). Previously, we found that a 5/6th nephrectomy model of CKD leads to an upregulation of miR-21-5p in the left ventricle, targeting peroxisome proliferator-activated receptor-α and altering the expression of numerous transcripts involved with fatty acid oxidation and glycolysis. In the present study, we evaluated the potential for knockdown or overexpression of miR-21-5p to regulate lipid content, lipid peroxidation, and mitochondrial respiration in H9C2 cells. Cells were transfected with anti-miR-21-5p (40 nM), pre-miR-21-5p (20 nM), or the appropriate scrambled oligonucleotide controls before lipid treatment in culture or as part of the Agilent Seahorse XF fatty acid oxidation assay. Overexpression of miR-21-5p attenuated the lipid-induced increase in cellular lipid content, whereas suppression of miR-21-5p augmented it. The abundance of malondialdehyde, a product of lipid peroxidation, was significantly increased with lipid treatment in control cells but attenuated in pre-miR-21-5p-transfected cells. This suggests that miR-21-5p reduces oxidative stress. The cellular oxygen consumption rate (OCR) was increased in both pre-miR-21-5p- and anti-miR-21-5p-transfected cells. Levels of intracellular ATP were significantly higher in anti-mR-21-5p-transfected cells. Pre-miR-21-5p blocked additional increases in OCR in response to etomoxir and palmitic acid. Conversely, anti-miR-21-5p-transfected cells exhibited reduced OCR with both etomoxir and palmitic acid, and the glycolytic capacity was concomitantly reduced. Together, these results indicate that overexpression of miR-21-5p attenuates both lipid content and lipid peroxidation in H9C2 cells. This likely occurs by reducing cellular lipid uptake and utilization, shifting cellular metabolism toward reliance on the glycolytic pathway. NEW & NOTEWORTHY Both overexpression and suppression of miR-21-5p augment basal and maximal mitochondrial respiration. Our data suggest that reliance on glycolytic and fatty acid oxidation pathways can be modulated by the abundance of miR-21-5p within the cell. miR-21-5p regulation of mitochondrial respiration can be modulated by extracellular lipids.

scholarly journals The metabolism of cholesterol in the presence of liver mitochondria from normal and thyroxine-treated rats

1965 ◽  
Vol 94 (3) ◽  
pp. 594-603 ◽  
Author(s):  
KA Mitropoulos ◽  
NB Myant
Keyword(s):  
Carbon Dioxide ◽  
Steam Distillation ◽  
Liver Mitochondria ◽  
Incubation Mixture ◽  
Side Chain ◽  
Volatile Fraction ◽  
Low Molecular Weight ◽  
Butanol Extract ◽  
Rate Limiting ◽  
Layer Chromatography

1. [26-(14)C]- and [4-(14)C]-Cholesterol were incubated with liver mitochondria from normal and thyroxine-treated rats, and the radioactivity was measured in the carbon dioxide evolved during the incubation, in a butanol extract of the incubation mixture and in a volatile fraction containing substances of low molecular weight derived from the side chain of cholesterol. The butanol extract was separated by paper chromatography into three radioactive fractions, one of which contained the steroids more polar than cholesterol. 2. The butanol extract from incubations with [4-(14)C]cholesterol contained a radioactive substance moving with the same R(F) as cholic acid on thin-layer chromatography. 3. After incubation with [26-(14)C]-cholesterol, 60-80% of the radioactivity extracted by steam-distillation of the incubation mixture at acid pH was recovered as [(14)C]propionic acid. 4. In the presence of [26-(14)C]cholesterol, mitochondria from thyroxine-treated rats produced more radioactivity in carbon dioxide and in the volatile fraction, and less radioactivity in the fraction containing the polar steroids, than did mitochondria from normal rats. In the presence of [4-(14)C]cholesterol, mitochondria from thyroxine-treated rats produced the same amount of radioactivity in the polar steroids as did normal mitochondria. 5. Thyroxine treatment had no effect on the capacity of the mitochondria to oxidize propionate to carbon dioxide. 6. These results are best explained by supposing that thyroxine stimulates a rate-limiting reaction leading to the cleavage of the side chain of cholesterol, but has little or no influence on the hydroxylations of the ring system or on the oxidation of the C(3) fragment removed from the side chain.

scholarly journals Reversible ATP-induced inactivation of branched-chain 2-oxo acid dehydrogenase

1980 ◽  
Vol 192 (1) ◽  
pp. 155-163 ◽  
Author(s):  
R Odessey
Keyword(s):  
Skeletal Muscle ◽  
Liver Mitochondria ◽  
Initial Activity ◽  
Rat Skeletal Muscle ◽  
Kidney Mitochondria ◽  
Physiological Conditions ◽  
Acid Dehydrogenase ◽  
Skeletal Muscle Mitochondria ◽  
Branched Chain

The branched chain 2-oxo acid dehydrogenase from rat skeletal muscle, heart, kidney and liver mitochondria can undergo a reversible activation-inactivation cycle in vitro. Similar results were obtained with the enzyme from kidney mitochondria of pig and cow. The dehydrogenase is markedly inhibited by ATP and the inhibition is not reversed by removing the nucleotide. The non-metabolizable ATP analogue adenosine 5′-[beta gamma-imido] triphosphate can block the effect of ATP when added with the nucleotide, but has no effect by itself, nor can it reverse the inhibition in mitochondria preincubated with ATP. These findings suggest that the branched chain 2-oxo acid dehydrogenase undergoes a stable modification that requires the splitting of the ATP gamma-phosphate group. In skeletal muscle mitochondria the rate of inhibition by ATP is decreased by oxo acid substrates and enhanced by NADH. The dehydrogenase can be reactivated 10-20 fold by incubation at pH 7.8 in a buffer containing Mg2+ and cofactors. Reactivation is blocked by NaF (25 mM). The initial activity of dehydrogenase extracted from various tissues of fed rats varies considerably. Activity is near maximal in kidney and liver whereas the dehydrogenase in heart and skeletal muscle is almost completely inactivated. These studies emphasize that comparisons of branched chain 2-oxo acid dehydrogenase activity under various physiological conditions or in different tissues must take into account its state of activation. Thus the possibility exists that the branched chain 2-oxo acid dehydrogenase may be physiologically regulated via a covalent mechanism.

scholarly journals Stimulation of Mitochondrial Fatty Acid Oxidation by Growth Hormone in Human Fibroblasts1

1997 ◽  
Vol 82 (12) ◽  
pp. 4208-4213 ◽  
Author(s):  
Kin-Chuen Leung ◽  
Ken K. Y. Ho
Keyword(s):  
Fatty Acid ◽  
Growth Factor ◽  
Lipid Oxidation ◽  
Palmitic Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Growth Factor I ◽  
Stimulation Of

In vivo administration of GH induces lipolysis and lipid oxidation. However, it is not clear whether the stimulation of lipid oxidation is a direct effect of GH or is driven by increased substrate supply secondary to lipolysis. An in vitro bioassay has been established for assessing β-oxidation of fatty acids in mitochondria, based on the measurement of conversion of tritiated palmitic acid to 3H2O by fibroblasts in culture. We have modified this assay to investigate whether GH stimulates fatty acid oxidation. GH stimulated oxidation of palmitic acid maximally by 26.7 ± 2.5% (mean ± sem; P < 0.0001). The stimulation was biphasic, with the oxidation rate increasing with increasing GH concentration to a peak response at 1.5 nmol/L and declining to a level not significantly different from control thereafter. Insulin-like growth factor-I at concentrations of up to 250 nmol/L had no significant effect on fatty acid oxidation. GH-binding protein attenuated the effect of GH. An anti-GH receptor (GHR) antibody (MAb263), which dimerizes the receptor and induces GH-like biological actions, significantly stimulated fatty acid oxidation. Another anti-GHR antibody (MAb5), which prevents receptor dimerization, suppressed GH action. In summary, GH directly stimulated fatty acid oxidation, an action not mediated by insulin-like growth factor-I. Dimerization of GHRs was necessary for this effect. This bioassay is a practical tool for studying the regulatory effects of GH on lipid oxidation.

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