THE UNCOUPLING OF OXIDATIVE PHOSPHORYLATION BY IONIZING RADIATION

1962 ◽  
Vol 40 (8) ◽  
pp. 1025-1042 ◽  
Author(s):  
J. F. Scaife ◽  
B. Hill
Keyword(s):  
Oxidative Phosphorylation ◽  
Liver Mitochondria ◽  
Cell Suspensions ◽  
Whole Body ◽  
X Rays ◽  
Succinate Oxidation ◽  
Mouse Ascites ◽  
Uncoupling Of Oxidative Phosphorylation

Whole body irradiation of rabbits or rats with X-rays or Co60γ-rays causes uncoupling of oxidative phosphorylation in thymus mitochondria, which is not prevented by the prior administration of AET. Whole body irradiation was not found to affect oxidative phosphorylation in liver or mouse ascites cell mitochondria. The radiation lesion can be repaired in vitro by the addition of cytochrome c, bovine serum albumin, or vitamin K1to mitochondria. Vitamin E and coenzyme Q10 were without effect. Both phosphorylating steps in the electron transport chain associated with succinate oxidation are affected by irradiation. The diphosphopyridine nucleotide dependent steps in the oxidation of α-ketoglutarate by thymus mitochondria are damaged by in vivo irradiation. Diphosphopyridine nucleotide levels of thymus and spleen but not liver or ascites cells are reduced by in vivo irradiation. No effect of in vitro irradiation on oxidative phosphorylation could be found for thymocyte cell suspensions, isolated thymus or liver mitochondria, or ascites or HeLa cell suspensions. Respiration of ascites or thymocyte cells was unaffected by in vitro irradiation.

THE UNCOUPLING OF OXIDATIVE PHOSPHORYLATION BY IONIZING RADIATION

1962 ◽  
Vol 40 (1) ◽  
pp. 1025-1042 ◽  
Author(s):  
J. F. Scaife ◽  
B. Hill
Keyword(s):  
Oxidative Phosphorylation ◽  
Liver Mitochondria ◽  
Cell Suspensions ◽  
Whole Body ◽  
X Rays ◽  
Succinate Oxidation ◽  
Mouse Ascites ◽  
Uncoupling Of Oxidative Phosphorylation

Whole body irradiation of rabbits or rats with X-rays or Co60γ-rays causes uncoupling of oxidative phosphorylation in thymus mitochondria, which is not prevented by the prior administration of AET. Whole body irradiation was not found to affect oxidative phosphorylation in liver or mouse ascites cell mitochondria. The radiation lesion can be repaired in vitro by the addition of cytochrome c, bovine serum albumin, or vitamin K1to mitochondria. Vitamin E and coenzyme Q10 were without effect. Both phosphorylating steps in the electron transport chain associated with succinate oxidation are affected by irradiation. The diphosphopyridine nucleotide dependent steps in the oxidation of α-ketoglutarate by thymus mitochondria are damaged by in vivo irradiation. Diphosphopyridine nucleotide levels of thymus and spleen but not liver or ascites cells are reduced by in vivo irradiation. No effect of in vitro irradiation on oxidative phosphorylation could be found for thymocyte cell suspensions, isolated thymus or liver mitochondria, or ascites or HeLa cell suspensions. Respiration of ascites or thymocyte cells was unaffected by in vitro irradiation.

UNCOUPLING OF OXIDATIVE PHOSPHORYLATION BY VANADATE

1966 ◽  
Vol 44 (7) ◽  
pp. 983-988 ◽  
Author(s):  
John N. Hathcock ◽  
C. H. Hill ◽  
S. B. Tove
Keyword(s):  
Electron Transport ◽  
Oxidative Phosphorylation ◽  
Adenosine Triphosphate ◽  
Adenosine Diphosphate ◽  
Liver Mitochondria ◽  
In Vitro Studies ◽  
Exchange Reactions ◽  
Uncoupling Of Oxidative Phosphorylation

The addition of ammonium metavanadate to the diet of chicks at a level to supply 25 parts per million vanadium uncoupled oxidative phosphorylation in mitochondria isolated from the livers. In vitro studies revealed that 1 mM vanadate uncoupled oxidative phosphorylation in liver mitochondria. This uncoupling was manifest whether succinate or β-hydroxybutyrate was used as the substrate, suggesting that all three phosphorylating sites associated with electron transport were uncoupled.At a concentration of 0.1 mM, vanadate increased the destruction of adenosine triphosphate by mitochondria. As the concentration of vanadate was increased the destruction of adenosine triphosphate became progressively less. The exchange reactions of adenosine triphosphate with orthophosphate and with adenosine diphosphate, catalyzed by liver mitochondria, were inhibited by 0.1 mM vanadate. These results suggest the possibility that the known toxic effects of vanadium in vivo are related to the uncoupling of oxidative phosphorylation.

scholarly journals Influence of ubiquinone on the inhibitory effect of adriamycin on mitochondrial oxidative phosphorylation

1984 ◽  
Vol 217 (2) ◽  
pp. 493-498 ◽  
Author(s):  
H Muhammed ◽  
C K R Kurup
Keyword(s):  
Oxidative Phosphorylation ◽  
Rat Heart ◽  
Liver Mitochondria ◽  
Inhibitory Effect ◽  
Oxidative Activity ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Succinate Oxidation ◽  
Exogenous Addition

The inhibition of succinate oxidation in both heart and liver mitochondria by the cardiotoxic anticancer antibiotic adriamycin in vitro was reversed to a large extent by exogenous ubiquinone-45. Inhibition of the oxidation of NAD+-linked substrates in heart and liver mitochondria responded differently to ubiquinone, the inhibition being reversed only in liver organelles. Administration of adriamycin inhibited oxidative phosphorylation in rat heart, kidney and liver mitochondria, the inhibition being highest in the heart organelles (about 50% for both NAD+-linked substrates and succinate). Exogenous addition of ubiquinone to mitochondria isolated from drug-treated animals did not reverse the inhibition. Administration of ubiquinone along with adriamycin did not change effectively the pattern of drug-mediated decrease in oxidative activity of the organelles, particularly in the heart.

ALDOSTERONE AND OXIDATIVE PHOSPHORYLATION IN LIVER MITOCHONDRIA

1966 ◽  
Vol 36 (1) ◽  
pp. 63-71 ◽  
Author(s):  
E. BEDRAK ◽  
V. SAMOILOFF
Keyword(s):  
Oxidative Phosphorylation ◽  
Mouse Liver ◽  
Electrolyte Concentration ◽  
Reaction Medium ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Male And Female ◽  
Single Intraperitoneal Injection ◽  
Uncoupling Of Oxidative Phosphorylation

SUMMARY A single intraperitoneal injection of 2 μg. d-aldosterone monoacetate/g. body weight produced a rapid, but temporary, uncoupling of oxidative phosphorylation in mouse liver mitochondria. This resulted in low P:O ratios in male and female animals of 1·21 and 1·52, respectively. The P:O ratio of females remained somewhat lower than the control levels but there was a progressive improvement in oxidative phosphorylation during the first 24 hr. after the injection leading to P: O ratios similar to those in the controls. Experiments in vitro showed that the uncoupling effects of aldosterone were related to its concentration in the reaction medium. Aldosterone added to fresh rat liver mitochondria, at concentrations of 10−10, 10−7 and 10−4m inhibited phosphorylation by 9·5, 77·1 and 95·1% and lowered P:O ratios to 2·46, 1·66 and 0·41, respectively. These changes in oxidative phosphorylation were not related to alteration in ATPase activity and were independent of mitochondrial electrolyte concentration.

Conformational Changes of Mitochondria associated with Uncoupling of Oxidative Phosphorylation in vivo and in vitro

Nature ◽  
1970 ◽  
Vol 226 (5242) ◽  
pp. 272-274 ◽  
Author(s):  
P. BUFFA ◽  
V. GUARRIERA-BOBYLEVA ◽  
U. MUSCATELLO ◽  
I. PASQUALI-RONCHETTI
Keyword(s):  
Oxidative Phosphorylation ◽  
Conformational Changes ◽  
Uncoupling Of Oxidative Phosphorylation

Oxidative phosphorylation and adenosine triphosphatase activity in the liver mitochondria of rats administered with phenylhydrazine and hydroiyzed glucose cycloacetoacetate

1969 ◽  
Vol 47 (3) ◽  
pp. 297-300 ◽  
Author(s):  
T. G. Reddi ◽  
M. C. Nath
Keyword(s):  
Oxygen Uptake ◽  
Oxidative Phosphorylation ◽  
Rat Liver ◽  
Adenosine Triphosphatase ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Partial Restoration ◽  
Atp Formation

The effect of phenylhydrazine and hydroiyzed product of glucose cycloacetoacetate (GCAh) administration on the activity of adenosine triphosphatase (ATPase) in rat-liver mitochondria has been investigated. The results are discussed in relation to the efficiency of mitochondrial oxidative phosphorylation. Phenylhydrazine was found to increase the ATPase activity both in vitro and in vivo. However, preincubation or treatment with hydrolyzed glucose cycloacetoacetate resulted in an appreciable depression of this phenylhydrazine-enhanced enzyme activity. The liver mitochondria from phenylhydrazine-administered rats showed very little difference in milligrams of total protein, but the homogenates had a high protein content as compared to the preparations from normal rats and rats administered with hydrolyzed glucose cycloacetoacetate. With citrate as the substrate, normal rat-liver mitochondria exhibited a P/O ratio of 3.0. With the same substrate, the liver mitochondria from phenylhydrazine-administered rats lowered the oxygen uptake and ATP formation, thereby resulting in a decreased P/O ratio of 2.4, whereas administration of hydrolyzed glucose cycloacetoacetate prior to phenylhydrazine resulted in a partial restoration in oxygen uptake and ATP formation, and thus yielded a P/O ratio of 2.8.

scholarly journals Radiosensitization of Prostate Cancers In Vitro and In Vivo to Erbium-filtered Orthovoltage X-rays Using Actively Targeted Gold Nanoparticles

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Allison M. Khoo ◽  
Sang Hyun Cho ◽  
Francisco J. Reynoso ◽  
Maureen Aliru ◽  
Kathryn Aziz ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
X Rays ◽  
Prostate Cancers
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