Trypanosoma lewisi: Oxygen uptake of rat liver mitochondria

1973 ◽  
Vol 43 (1) ◽  
pp. 53-62
Author(s):  
Clarence M. Lee ◽  
Essica Barnabas
Keyword(s):  
Oxygen Uptake ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Trypanosoma Lewisi

ENZYME INHIBITION BY DERIVATIVES OF PHENOTHIAZINE

1952 ◽  
Vol 30 (6) ◽  
pp. 443-446
Author(s):  
H. B. Collier ◽  
G. M. Allenby
Keyword(s):  
Oxygen Uptake ◽  
Cytochrome Oxidase ◽  
Enzyme Inhibition ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Cytochrome Oxidase Activity ◽  
Derivatives Of

The succinoxidase activity of rat-liver mitochondria was strongly inhibited by the following compounds (concentration for 50% reduction in rate of oxygen uptake is given in brackets): phenothiazine (1.4 × 10−5 M), phenothiazine sulphoxide (2.8 × 10−5 M), and phenothiazone (5.4 × 10−5 M). Thionol was only slightly inhibitory. The cytochrome oxidase activity of mitochondria was not inhibited by any of these compounds.

scholarly journals The action of paraquat and diquat on the respiration of liver cell fractions

1968 ◽  
Vol 109 (5) ◽  
pp. 757-761 ◽  
Author(s):  
J C Gage
Keyword(s):  
Oxygen Uptake ◽  
Nadph Oxidase ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Nadh Oxidase ◽  
Liver Microsomes ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Rat Liver Microsomes ◽  
Nadph Oxidase Activity

1. Paraquat and diquat produce only a slight increase in the oxygen uptake of rat liver mitochondria, and it is likely that they do not penetrate the mitochondrial membrane. 2. In mitochondrial fragments inhibited by antimycin A or by Amytal, both substances stimulate oxygen uptake with NADH or β-hydroxybutyrate as substrate but not with succinate. The NADH dehydrogenase of the respiratory chain appears to be involved, at a site only partially inhibited by Amytal. 3. An NADPH oxidase activity is stimulated in rat liver microsomes by diquat, and to a smaller extent by paraquat; diquat also causes an NADH oxidase activity to develop. The effect is not inhibited by carbon monoxide or p-chloromercuribenzoate, and it is probable that a flavoprotein is involved by a mechanism not requiring thiol groups. 4. One molecule of oxygen can oxidize two molecules of NADPH in the stimulated microsomal system, the hydrogen peroxide produced being broken down by a catalase activity in the microsomes. 5. Diquat can stimulate NADH oxidase and NADPH oxidase activity in the postmicrosomal soluble fraction; the enzyme involved may be DT-diaphorase. 6. The mechanism of these reactions and their significance in relation to the toxicity of the dipyridilium compounds are discussed.

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.

Effects of 5-5'-Diphenyl-2-thiohydantoin (DPTH) and Thyroxine on the Ultrastructure and Chemical Composition of Rat Liver

1971 ◽  
Vol 29 ◽  
pp. 570-571
Author(s):  
E. A. Elfont ◽  
R. B. Tobin ◽  
D. G. Colton ◽  
M. A. Mehlman
Keyword(s):  
Chemical Composition ◽  
Rat Liver ◽  
Future Study ◽  
Mode Of Action ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Effective Inhibitor ◽  
Biochemical Effects ◽  
Glycerophosphate Dehydrogenase ◽  
Stimulation Of

Summary5,-5'-diphenyl-2-thiohydantoin (DPTH) is an effective inhibitor of thyroxine (T4) stimulation of α-glycerophosphate dehydrogenase in rat liver mitochondria. Because this finding indicated a possible tool for future study of the mode of action of thyroxine, the ultrastructural and biochemical effects of DPTH and/or thyroxine on rat liver mere investigated.Rats were fed either standard or DPTH (0.06%) diet for 30 days before T4 (250 ug/kg/day) was injected. Injection of T4 occurred daily for 10 days prior to sacrifice. After removal of the liver and kidneys, part of the tissue was frozen at -50°C for later biocheailcal analyses, while the rest was prefixed in buffered 3.5X glutaraldehyde (390 mOs) and post-fixed in buffered 1Z OsO4 (376 mOs). Tissues were embedded in Araldlte 502 and the sections examined in a Zeiss EM 9S.Hepatocytes from hyperthyroid rats (Fig. 2) demonstrated enlarged and more numerous mitochondria than those of controls (Fig. 1). Glycogen was almost totally absent from the cytoplasm of the T4-treated rats.

Sign in / Sign up

Export Citation Format

Share Document