scholarly journals Rat liver mitochondria prepared in mannitol media demonstrate increased mitochondrial volumes compared with mitochondria prepared in sucrose media. Relationship to the effect of glucagon on mitochondrial function

1984 ◽  
Vol 221 (1) ◽  
pp. 147-152 ◽  
Author(s):  
D E Whipps ◽  
A P Halestrap
Keyword(s):  
Liver Mitochondria ◽  
Mitochondrial Metabolism ◽  
Rat Liver Mitochondria ◽  
Pyruvate Metabolism ◽  
Succinate Oxidation ◽  
Isolation Medium ◽  
Matrix Volume ◽  
Sucrose Medium ◽  
Mitochondrial Volume ◽  
Citrulline Synthesis

Liver mitochondria isolated from glucagon-treated rats by using both mannitol- and sucrose-based media showed enhanced uncoupled succinate oxidation, pyruvate metabolism and citrulline synthesis. Mitochondria prepared in mannitol medium showed some stimulation of these parameters compared with those prepared in sucrose medium. This was accompanied by an increase in matrix volume of about 20%. Some [14C]mannitol became permanently associated with mitochondria during preparation. It is suggested that mannitol may enter mitochondria during their preparation and cause swelling. The presence of 4mM-phosphate in the sucrose isolation medium stimulated the same parameters as did glucagon treatment, and also caused an increase in matrix volume of about 20%. These results confirm the conclusion that the mitochondrial volume may be important in the regulation of mitochondrial metabolism. They contradict the conclusion of others [Siess (1983) Hoppe-Seyler's Z. Physiol. Chem. 364, 279-290, 835-838] that mannitol rather than sucrose should be used when studying hormonal effects on mitochondrial metabolism. Reasons for the discrepancies in the results between groups studying the effects of hormones on mitochondrial metabolism are discussed.

scholarly journals SEDIMENTATION PROPERTIES OF RAT LIVER MITOCHONDRIA

1970 ◽  
Vol 46 (1) ◽  
pp. 17-26 ◽  
Author(s):  
John N. Loeb ◽  
Daniel V. Kimberg
Keyword(s):  
Rat Liver ◽  
Gradient Centrifugation ◽  
Sucrose Density Gradient ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Electron Microscopic ◽  
Sucrose Density Gradient Centrifugation ◽  
Sedimentation Behavior ◽  
Sucrose Medium ◽  
Mitochondrial Volume

A prediction of the velocity of sedimentation of rat liver mitochondria in sucrose gradients is made on the basis of recent measurements of the size of isolated mitochondria suspended in sucrose medium and the model proposed by Bentzel and Solomon to describe the osmotic behavior of mitochondria. The experimentally observed velocity is extremely close to the predicted value and confirms by a different approach the estimate of mitochondrial volume made by Baudhuin and Berthet on the basis of electron microscopic measurements. Because cortisone treatment of rats is known to result in a marked increase in mitochondrial size as observed under the electron microscope, mitochondria were co-isolated from livers of control and cortisone-treated animals, and the sedimentation behavior of the mixtures was examined by sucrose density gradient centrifugation. Mitochondria from cortisone-treated animals were found to sediment 1.4 times as rapidly as those from control animals, indicating that their increased size cannot entirely be due to an increased imbibition of fluid from the surrounding sucrose medium, and that the change in size must at least in part be due to a change in content of nondiffusible mitochondrial components. Although the increase in sedimentation velocity of mitochondria from cortisone-treated animals is striking, it is less than that predicted solely on the basis of their size relative to that of control mitochondria. It is concluded that the increases in mitochondrial size and content of nondiffusible components produced by cortisone treatment are accompanied by alterations in mitochondrial composition as well.

scholarly journals Adaptive changes in the capacity of systems used for the synthesis of citrulline in rat liver mitochondria in response to high- and low-protein diets

1974 ◽  
Vol 142 (2) ◽  
pp. 359-364 ◽  
Author(s):  
J. D. McGivan ◽  
Norah M. Bradford ◽  
J. B. Chappell
Keyword(s):  
Nitrogen Source ◽  
High Protein Diet ◽  
Liver Mitochondria ◽  
High Protein ◽  
Protein Diet ◽  
Rat Liver Mitochondria ◽  
Standard Diet ◽  
Adaptive Changes ◽  
Low Protein ◽  
Citrulline Synthesis

1. Citrulline synthesis was measured in mitochondria from rats fed on a standard diet, a high-protein diet, or on glucose. 2. With NH4Cl as the nitrogen source the rate of citrulline synthesis was higher in mitochondria from rats fed on a high-protein diet than in those from rats fed on a standard diet. When rats were fed solely on glucose the rate of synthesis of citrulline from NH4Cl was very low. 3. With glutamate as the nitrogen source the relative rates of citrulline synthesis were much lower than when NH4Cl was present, but similar adaptive changes occurred. 4. The activity of the mitochondrial glutamate-transporting system increased two to three times on feeding rats on a high-protein diet, but the Km for glutamate was unchanged. 5. Adaptive changes in certain intramitochondrial enzymes were also measured. 6. The results were interpreted to indicate that when an excess of substrate was present, citrulline synthesis from NH4Cl was rate-limited by the intramitochondrial concentration of N-acetyl-glutamate, but citrulline synthesis from glutamate was rate-limited primarily by the activity of the glutamate-transporting system.

scholarly journals Relationship between the Rate of Citrulline Synthesis and Bulk Changes in the Intramitochondrial ATP/ADP Ratio in Rat-Liver Mitochondria

1981 ◽  
Vol 113 (2) ◽  
pp. 295-302 ◽  
Author(s):  
Ron J. A. WANDERS ◽  
George M. WOERKOM ◽  
Ron F. NOOTEBOOM ◽  
Alfred J. MEIJER ◽  
Joseph M. TAGER
Keyword(s):  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Citrulline Synthesis

scholarly journals Energetics of citrulline synthesis by rat liver mitochondria.

1981 ◽  
Vol 256 (14) ◽  
pp. 7287-7297
Author(s):  
J.R. Williamson ◽  
R. Steinman ◽  
K. Coll ◽  
T.L. Rich
Keyword(s):  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Citrulline Synthesis

Oxidative energy metabolism in germ-free and conventional rat liver mitochondria

1975 ◽  
Vol 228 (2) ◽  
pp. 526-529 ◽  
Author(s):  
DL Sewell ◽  
BS Wostmann ◽  
C Gairola ◽  
MI Aleem
Keyword(s):  
Wistar Rats ◽  
Liver Mitochondria ◽  
The State ◽  
Rat Liver Mitochondria ◽  
Succinate Oxidation ◽  
Germ Free ◽  
Adult Rat ◽  
Respiration Rates ◽  
Oxidative Energy Metabolism ◽  
Beta Hydroxybutyrate

The ADP:O ratios and State 3 (ADP-stimulated) and State 4 (controlled) rates of succinate, beta-hydroxybutyrate, isocitrate, glutamate, pyruvate + malate, alpha-ketoglutarate, and ascorbate + N,N,N',N'-tetramethylphenylenediamine (TMPD) oxidation were examined in liver mitochondria from germ-free and conventional rats of both Lobund Wistar (100-day-old) and Fisher (120-day-old) strains. The State 3 respiration rates of isolated mitochondria from germ-free and conventional rats were comparable except for the rate of succinate oxidation in the Wistar rats, which was significantly lower (approx. 10%). The State 4 respiration rates were generally lower in mitochondria isolated from germ-free Fisher rats (approx. 8%) and significantly lower (approx. 18%) in germ-free Wistar rats. The ADP:O ratios were similar in germ-free and conventional rats. Serum thyroxine concentrations indicated delayed maturation of thyroid function in young germ-free rats, but adult animals had concentrations similar to those found in conventional rats. The results indicate that, although absence of a microflora results in a 20-30% reduction in metabolic rate, the germ-free state has little influence on the functional respiration or oxidative phosphorylation of mitochondria isolated from the liver of the adult rat.

Quantitation of effects on mitochondrial swelling: some effects of ATP and aging

1962 ◽  
Vol 17 (6) ◽  
pp. 979-984 ◽  
Author(s):  
Charles McGaughey
Keyword(s):  
Aging Time ◽  
Quantitative Measurement ◽  
Liver Mitochondria ◽  
Inhibitory Effect ◽  
Rate Of Change ◽  
Mitochondrial Swelling ◽  
Rat Liver Mitochondria ◽  
Logarithmic Function ◽  
Swelling Rate ◽  
Mitochondrial Volume

A method has been devised for the quantitative measurement of relative effects of substances or conditions on rate of change of mitochondrial volume. It can be used to study the effects progressively as the mitochondria swell. By this means, the effects of adenosine triphosphate (ATP) and aging on mitochondrial swelling were investigated. It was found that at constant mitochondrial volume, the rate of change of volume is a logarithmic function of aging time. The swelling of fresh mitochondria was mildly inhibited by ATP at very low volumes. Aging of rat liver mitochondria caused this inhibitory effect to be replaced by enhancement of swelling, which became greater in magnitude and was retained through larger volumes as aging time increased. The swelling enhancement was followed by inhibition, the magnitude of which increased with further swelling. The inhibitory effect of ATP on swelling of mouse liver mitochondria underwent a sudden marked increase at a particular mitochondrial volume independent of aging time and time of ATP exposure. At lower volumes the effect of ATP increased with aging time and swelling rate, whereas at larger volumes this relation ceased to be apparent. The possible significance of these results is discussed. Submitted on January 22, 1962

Inhibition of Succinic Dehydrogenase and F0F1-ATP Synthase by 4,4'-Diisothiocyanatostilbene-2,2'-disulfonic Acid (DIDS)

1997 ◽  
Vol 52 (11-12) ◽  
pp. 799-806 ◽  
Author(s):  
Celene F. Bernardes ◽  
Jose R. Meyer-Fernandes ◽  
Orlando B. Martins ◽  
Anibal E. Vercesi
Keyword(s):  
Succinic Dehydrogenase ◽  
Atp Synthesis ◽  
Liver Mitochondria ◽  
Disulfonic Acid ◽  
Rat Liver Mitochondria ◽  
Dependent Manner ◽  
Submitochondrial Particles ◽  
Succinate Oxidation ◽  
Hydrolytic Activities ◽  
Dose Dependent

Abstract This study shows that incubation of rat liver mitochondria in the presence of the thiol/ amino reagent 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DID S) is followed by inhibition of both succinate supported respiration and oxidative phosphorylation. Half-maximal inhibition of succinic dehydrogenase activity and succinate oxidation by mitochondria was attained at 55.3 and 60.8 μm DIDS, respectively. DIDS did inhibit the net ATP synthesis and ATP ⇔ [32P]Pi exchange reaction catalyzed by submitochondrial particles in a dose-dependent manner (Ki= 31.7 μm and Ki = 32.7 μm), respectively. The hydrolytic activities of uncoupled heart submitochondrial particles and purified F 1 -ATPase were also inhibited 50% by 31.9 and 20.9 μm DIDS, respectively.

Effect of propionate and pyruvate on citrulline synthesis and ATP content in rat liver mitochondria

1979 ◽  
Vol 90 (1) ◽  
pp. 327-332 ◽  
Author(s):  
Liliane Cathelineau ◽  
Françoise P. Petit ◽  
François X Coudé ◽  
Pierre P. Kamoun
Keyword(s):  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Atp Content ◽  
Citrulline Synthesis
Sign in / Sign up

Export Citation Format

Share Document