scholarly journals The effect of osmotic ‘shock’ on the swelling pattern and respiratory control of rat-liver mitochondria

1967 ◽  
Vol 104 (1) ◽  
pp. 71-77 ◽  
Author(s):  
S Streichman ◽  
Y Avi-Dor
Keyword(s):  
Rat Liver ◽  
Osmotic Shock ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria

scholarly journals The maturation of the inner membrane of foetal rat liver mitochondria. An example of a positive-feedback mechanism

1975 ◽  
Vol 150 (3) ◽  
pp. 477-488 ◽  
Author(s):  
J K Pollak
Keyword(s):  
Oxidative Phosphorylation ◽  
Rat Liver ◽  
Mitochondrial Membrane ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Neonatal Rat ◽  
Rat Liver Mitochondria ◽  
Inner Mitochondrial Membrane ◽  
Mature Adult ◽  
Foetal Rat

A new method was devised for the isolation of foetal and neonatal rat lvier mitochondria, giving higher yields than conventional methods. 2. During development from the perinatal period to the mature adult, the ratio of cytochrome oxidase/succinate-cytochrome c reductase changes. 3. The inner mitochondrial membrane of foetal liver mitochondria possesses virtually no osmotic activity; the permeability to sucrose decreases with increasing developmental age. 4. Foetal rat liver mitochondria possess only marginal respiratory control and do not maintain Ca2+-induced respiration; they also swell in respiratory-control medium in the absence of substrate. ATP enhances respiratory control and prevents swelling, adenylyl imidodiphosphate, ATP+atractyloside enhance the R.C.I. (respiratory control index), Ca2+-induced respiratory control and prevent swelling, whereas GTP and low concentrations of ADP have none of these actions. It is concluded that the effect of ATP depends on steric interaction with the inner mitochondrial membrane. 5. When 1-day pre-partum foetuses are obtained by Caesarean section and maintained in a Humidicrib for 90 min, mitochondrial maturation is ‘triggered’, so that their R.C.I. is enhanced and no ATP is required to support Ca2+-dependent respiratory control or to inhibit mitochondrial swelling. 6. It is concluded that foetal rat liver mitochondria in utero do not respire, although they are capable of oxidative phosphorylation in spite of their low R.C.I. The different environmental conditions which the neonatal rat encounters ex utero enable the hepatic mitochondria to produce ATP, which interacts with the inner mitochondrial membrane to enhance oxidative phosphorylation by an autocatalytic mechanism.

scholarly journals Transport of reduced nicotinamide–adenine dinucleotide into mitochondria of rat white adipose tissue

1970 ◽  
Vol 116 (2) ◽  
pp. 229-233 ◽  
Author(s):  
B. H. Robinson ◽  
M. L. Halperin
Keyword(s):  
Adipose Tissue ◽  
Rat Liver ◽  
White Adipose Tissue ◽  
Nicotinamide Adenine Dinucleotide ◽  
Aspartate Aminotransferase ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Nadh Oxidation ◽  
Rat Liver Mitochondria ◽  
Reduced Nicotinamide Adenine Dinucleotide

Mitochondria from rat white adipose tissue were prepared, exhibiting good respiratory control and P/O ratios. They would not oxidize NADH unless NNN′N′-tetramethyl-p-phenylenediamine was added as a carrier of reducing equivalents. These mitochondria were found to oxidize neither l-glycerol 3-phosphate nor l-glutamate plus l-malate at significant rates. The activity of aspartate aminotransferase in these mitochondria was found to be low compared with that found in rat liver mitochondria. As a consequence of this, the adipose-tissue mitochondria exhibited very low rates of cytoplasmic NADH oxidation in a reconstituted Borst (1962) cycle compared with liver mitochondria.

Uncoupling activity of endogenous free fatty acids in rat liver mitochondria

1978 ◽  
Vol 56 (2) ◽  
pp. 111-116 ◽  
Author(s):  
Samuel H. P. Chan ◽  
Edward Higgins Jr.
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Free Fatty Acids ◽  
Rat Liver ◽  
Respiratory Control ◽  
Aging Effect ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria

Changes in the respiratory control index (RCI) and ADP:O ratio were found to be related to alterations in the free fatty acids levels of rat liver mitochondria aging in 0.25 M sucrose–Tris buffer at 0 °C. Free fatty acid levels increased with time after isolation of mitochondria while a concomitant decrease in the RCI and ADP:O ratio occurred. The changes in free fatty acid levels corresponded with the reported increasing levels of phospholipase A activity in aged mitochondrial preparations. Washing these mitochondria with sucrose buffer containing 1% defatted bovine serum albumin (BSA) counteracted the aging effect on the RCI (e.g., 2.5 to 3.5) and reduced the free fatty acid levels (e.g., 50 to 16 nmol/mg protein). This reversible phenomenon could be repeated several times during the in vitro aging at 0 °C. Use of 125I-iodinated BSA showed that approximately 5 μg BSA/mg mitochondria was adsorbed by the mitochondrial membranes during washing. These results indicate a direct correlation between the level of endogenous fatty acids and the uncoupling of mitochondrial oxidative phosphorylation. The mechanism of counteracting the aging effect by BSA involves the removal of some of the free fatty acids.

scholarly journals Membrane-modifying properties of hydrated fullerene C60 in combination with Spirulina platensis cell culture

Biologija ◽  
2019 ◽  
Vol 64 (4) ◽  
Author(s):  
Tatyana Ovsyannikova ◽  
Oksana Falko ◽  
Alina Kovalenko ◽  
Michael Goloiad ◽  
Olga Lipina ◽  
...  
Keyword(s):  
Rat Liver ◽  
Spirulina Platensis ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Fullerene C60 ◽  
Rat Liver Mitochondria ◽  
Blue Green Algae ◽  
Rate Of Oxygen Consumption ◽  
A Cell ◽  
Free Radical Lipid

The study is devoted to the development of new promising nanocomponent compositions with membrane-modulating properties. The effect of a solution of hydrated fullerene C60 and a cell suspension of blue-green algae Spirulina platensis on the activity of free radical lipid peroxidation and oxidative phosphorylation in mitochondria of rat liver was studied. Fullerene C60 and suspension of Spirulina platensis cells were administered to Wistar rats for 30 days, once a day, intragastrically, both jointly and singly. The rate of oxygen consumption of phosphorylating and non-phosphorylating mitochondria (in V3 and V4 states), the rate and efficiency of ADP phosphorylation (ADP/Δt and ADP/O), respiratory control coefficient (RC) were changed in rat liver mitochondria. In the same samples, the concentration of diene, triene, oxodiene, and tetraene fatty acids was measured. The results of our studies have shown that the solution of hydrated fullerene C60 serves as a structural modifier of the lipid bilayer of cell membranes, the effect of which can be corrected by using an antioxidant component such as a suspension of Spirulina platensis cells.

scholarly journals The nature of the calcium ion efflux induced in rat liver mitochondria by the oxidation of endogenous nicotinamide nucleotides

1980 ◽  
Vol 188 (1) ◽  
pp. 113-118 ◽  
Author(s):  
D G Nicholls ◽  
M D Brand
Keyword(s):  
Membrane Potential ◽  
Rat Liver ◽  
Calcium Ion ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Critical Value ◽  
Mitochondrial Damage ◽  
Rat Liver Mitochondria ◽  
Ion Efflux ◽  
Complete Collapse

Ca2+ efflux from rat liver mitochondria can occur when endogenous nicotinamide nucleotides are oxidized. It is suggested that nicotinamide nucleotide induced by acetoacetate sensitizes the mitochondria to damaage resulting from the accumulation of Ca2+ in the presence of Pi. Thus, acetoacetate-induced Ca2+ efflux is associated with a loss of respiratory control. Both the effluxes induced by acetoacetate and by high Ca2+ accumulation are prevented by ATP plus oligomycin, although these agents do not prevent the endoagenous nicotinamide nucleotides from becoming oxidized on addition of acetoacetate. Acetoacetate addition only results in Ca2+ release if the Ca2+ and Pi concentration are above a critical value. The acetoacetate-induced Ca2+ effflux is exactly paralled by the virtually complete collapse of the membrane potential. The presence of acetoacetate decreases the concentration of total Ca2+ necessary to induced mitochondrial damage by about 130 nmol of Ca2+/mg of protein. It is concluded that acetoacetate-induced efflux occurs by reversal of the Ca2+ uniporter after the collapse of the membrane potential.

scholarly journals Hormone-initiated maturation of rat liver mitochondria after birth

1980 ◽  
Vol 186 (1) ◽  
pp. 361-367 ◽  
Author(s):  
R Sutton ◽  
J K Pollak
Keyword(s):  
Cyclic Amp ◽  
Rat Liver ◽  
Beta Blocker ◽  
Adenine Nucleotide ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Energy Transduction ◽  
Rat Liver Mitochondria ◽  
Maturation Process ◽  
High Concentrations

1. The injection of adrenaline, glucagon or cyclic AMP into foetal rats in utero initiates the maturation of energy transduction in rat liver mitochondria before birth. 2. The injection of the beta-blocker, propranolol, prevents this maturation process. 3. The maturation of mitochondrial energy transduction is measured in terms of the increase in the respiratory control index and mitochondrial adenine nucleotide concentration. 4. It is postulated that the actions of the hormones, acting through cyclic AMP, affect glycogenolysis and glycolysis to give rise to transient localized high concentrations of ATP. 5. It is the ATP that acts as the molecular trigger, effecting mitochondrial maturation.

Sign in / Sign up

Export Citation Format

Share Document