Effect of thyroid state and cold exposure on rat liver mitochondrial protein mass and function

1991 ◽  
Vol 131 (1) ◽  
pp. 67-73 ◽  
Author(s):  
S. Iossa ◽  
G. Liverini ◽  
A. Barletta
Keyword(s):  
Oxidative Phosphorylation ◽  
Rat Liver ◽  
Cold Exposure ◽  
Oxidative Metabolism ◽  
Mitochondrial Protein ◽  
The Other ◽  
Thyroid State ◽  
Protein Mass ◽  
Palmitoyl Carnitine ◽  
And Function

ABSTRACT The effects of thyroid state on liver mitochondrial protein mass was investigated in rats at 24 and 4 °C, as was oxidative phosphorylation using substrates which represent the final catabolic products of the metabolic fuels. In rats at 24 °C, a significant increase in mitochondrial protein mass (about +40%) was observed only in hyperthyroid animals, while a significant increase due to cold exposure was found in hypothyroid (+ 45%) and euthyroid (+ 35%) rats. In rats at 24 °C, hypothyroidism significantly decreased the oxidation of glutamate and palmitoyl carnitine but not of pyruvate, while hyperthyroidism only increased the oxidation of palmitoyl carnitine. On the other hand, exposure to cold significantly increased the oxidation of glutamate and pyruvate only in the presence of tri-iodothyronine. Our results underline not only the fact that a simple and single hypothesis for thyroid effects cannot be adopted, but also that any study concerning oxidative metabolism should be carried out using different substrates and involving different pathways of oxidation. Journal of Endocrinology (1991) 131, 67–73

Gender dimorphism in rat liver mitochondrial oxidative metabolism and biogenesis

2005 ◽  
Vol 289 (2) ◽  
pp. C372-C378 ◽  
Author(s):  
Roberto Justo ◽  
Jordi Boada ◽  
Margalida Frontera ◽  
Jordi Oliver ◽  
Jordi Bermúdez ◽  
...  
Keyword(s):  
Gender Differences ◽  
Protein Content ◽  
Rat Liver ◽  
Oxidative Metabolism ◽  
Mitochondrial Protein ◽  
Electron Microscopic ◽  
Gender Dimorphism ◽  
Protein Levels ◽  
Mitochondrial Fractions ◽  
Mitochondrial Oxidative Metabolism

In the present study, we have investigated gender differences in rat liver mitochondrial oxidative metabolism. Total mitochondrial population (M) as well as the heavy (M1), medium (M3), and light (M8) mitochondrial fractions obtained by means of differential centrifugation steps at 1,000, 3,000, and 8,000 g, respectively, were isolated. Electron microscopic analysis was performed and mitochondrial protein content and cardiolipin levels, mitochondrial O2 flux, ATP synthase activity, mitochondrial membrane potential, and mitochondrial transcription factor A (TFAM) protein levels were measured in each sample. Our results indicate that mitochondria from females have higher protein content and higher cardiolipin levels, greater respiratory and phosphorylative capacities, and more-energized mitochondria in respiratory state 3. Moreover, protein levels of TFAM were four times greater in females than in males. Gender differences in the aforementioned parameters were more patent in the isolated heavy M1 and M3 mitochondrial fractions. The present study demonstrates that gender-related differences in liver mitochondrial function are due mainly to a higher capacity and efficiency of substrate oxidation, likely related to greater mitochondrial machinery in females than in males, which is in accord with greater mitochondrial differentiation in females.

scholarly journals Alteration in gene expression of branched-chain keto acid dehydrogenase kinase but not in gene expression of its substrate in the liver of clofibrate-treated rats

1996 ◽  
Vol 317 (2) ◽  
pp. 411-417 ◽  
Author(s):  
Harbhajan S. PAUL ◽  
Wei-Qun LIU ◽  
Siamak A. ADIBI
Keyword(s):  
Gene Expression ◽  
Rat Liver ◽  
Fold Increase ◽  
Branched Chain Amino Acids ◽  
The Other ◽  
Mrna Levels ◽  
Keto Acid ◽  
Protein Mass ◽  
Acid Dehydrogenase ◽  
Branched Chain

We previously showed that the oxidation of branched-chain amino acids is increased in rats treated with clofibrate [Paul and Adibi (1980) J. Clin. Invest. 65, 1285–1293]. Two subsequent studies have reported contradictory results regarding the effect of clofibrate treatment on gene expression of branched-chain keto acid dehydrogenase (BCKDH) in rat liver. Furthermore, there has been no previous study of the effect of clofibrate treatment on gene expression of BCKDH kinase, which regulates the activity of BCKDH by phosphorylation. The purpose of the present study was to investigate the above issues. Clofibrate treatment for 2 weeks resulted in (a) a 3-fold increase in the flux through BCKDH in mitochondria isolated from rat liver, and (b) a modest but significant increase in the activity of BCKDH. However, clofibrate treatment had no significant effect on the mass of E1α, E1β, and E2 subunits of BCKDH or the abundance of mRNAs encoding these subunits. On the other hand, clofibrate treatment significantly reduced the activity, the protein mass and the mRNA levels of BCKDH kinase in the liver. In contrast to the results obtained in liver, clofibrate treatment had no significant effect on any of these parameters of BCKDH kinase in the skeletal muscle. In conclusion, our results show that clofibrate treatment increases the activity of BCKDH in the liver and the mechanism of this effect is the inhibition of gene expression of the BCKDH kinase.

scholarly journals The Swelling of Rat Liver Mitochondria by Thyroxine and its Reversal

1959 ◽  
Vol 5 (1) ◽  
pp. 97-108 ◽  
Author(s):  
Albert L. Lehninger ◽  
Betty Lou Ray ◽  
Marion Schneider
Keyword(s):  
Oxidative Phosphorylation ◽  
Temperature Coefficient ◽  
Oxidation State ◽  
Respiratory Chain ◽  
Rat Liver ◽  
Mitochondrial Membrane ◽  
Ph Dependence ◽  
Liver Mitochondria ◽  
The Other ◽  
Rat Liver Mitochondria

The in vitro swelling action of L-thyroxine on rat liver mitochondria as examined photometrically represents an acceleration of a process which the mitochondria are already inherently capable of undergoing spontaneously, as indicated by the identical kinetic characteristics and the extent of thyroxine-induced and spontaneous swelling, the nearly identical pH dependence, and the fact that sucrose has a specific inhibitory action on both types of swelling. However, thyroxine does not appear to be a "catalyst" or coenzyme since it does not decrease the temperature coefficient of spontaneous swelling. The temperature coefficient is very high, approximately 6.0 near 20°. Aging of mitochondria at 0° causes loss of thyroxine sensitivity which correlates closely with the loss of bound DPN from the mitochondria, but not with loss of activity of the respiratory chain or with the efficiency of oxidative phosphorylation. Tests with various respiratory chain inhibitors showed that the oxidation state of bound DPN may be a major determinant of thyroxine sensitivity; the oxidation state of the other respiratory carriers does not appear to influence sensitivity to thyroxine. These facts and other considerations suggest that a bound form of mitochondrial DPN is the "target" of the action of thyroxine. The thyroxine-induced swelling is not reversed by increasing the osmolar concentration of external sucrose, but can be "passively" or osmotically reversed by adding the high-particle weight solute polyvinylpyrrolidone. The mitochondrial membrane becomes more permeable to sucrose during the swelling reaction. On the other hand, thyroxine-induced swelling can be "actively" reversed by ATP in a medium of 0.15 M KCl or NaCl but not in a 0.30 M sucrose medium. The action of ATP is specific; ADP, Mn++, and ethylenediaminetetraacetate are not active. It is concluded that sucrose is an inhibitor of the enzymatic relationship between oxidative phosphorylation and the contractility and permeability properties of the mitochondrial membrane. Occurrence of different types of mitochondrial swelling, the intracellular factors affecting the swelling and shrinking of mitochondria, as well as the physiological significance of thyroxine-induced swelling are discussed.

Effect of prolonged cold exposure on oxidative phosphorylation and adenosinetriphosphatase activity of rat liver tissue

1959 ◽  
Vol 196 (4) ◽  
pp. 890-892 ◽  
Author(s):  
John P. Hannon
Keyword(s):  
Oxidative Phosphorylation ◽  
Rat Liver ◽  
Cold Exposure ◽  
Liver Tissue ◽  
Exposed Group ◽  
Lower Activity ◽  
Significant Lowering ◽  
Liver Homogenates ◽  
Calcium And Magnesium

Liver homogenates from control and one month cold-exposed (5 ± 1°C) rats were assayed for the P/O ratios characteristic of succinate and ß-hydroxybutyrate oxidations and for the level of adenosinetriphosphatase activity. With both substrates a significant lowering of the P/O ratio was observed in the cold-exposed group. Measurements of adenosinetriphosphatase activity in water homogenates showed that calcium and magnesium had strong activating effects. Little difference was found between control and experimental preparations except where both ions were used simultaneously. Here, the tissue from the cold-exposed group exhibited a slightly lower activity than the controls.

Evaluation of oxidative phosphorylation in hearts from euthyroid, hypothyroid, and hyperthyroid rats

1978 ◽  
Vol 235 (5) ◽  
pp. C212-C219 ◽  
Author(s):  
K. Nishiki ◽  
M. Erecinska ◽  
D. F. Wilson ◽  
S. Cooper
Keyword(s):  
Oxidative Phosphorylation ◽  
Mitochondrial Respiration ◽  
Adenine Nucleotides ◽  
Mitochondrial Protein ◽  
Respiratory Control ◽  
Perfused Heart ◽  
Thyroid State ◽  
Oxidation Reduction ◽  
Tightly Coupled ◽  
Energy Relationships

The energy relationships between cytosolic and mitochondrial metabolism were studied in the hearts from euthyroid, hypothyroid, and hyperthyroid rats. Isolated mitochondria showed high respiratory control ratios and impermeability to exogenous NADH. Hypo- and hyperthyroidism, respectively, resulted in lower and higher contents of both cytochromes per mitochondrion and mitochondrial protein per gram of wet weight of heart without changes in the ratio of cytochrome c to cytochrome aa3. In isolated perfused heart, the hyperthyroid state led to an increase in work rate and thereby an elevation of Vo2, which resulted in an increase oxidation-reduction turnover number for the cytochromes. An agreement was found between [ATP]/[ADP][Pi] of cytosolic free adenine nucleotides and the value calculated from a mathematical model of mitochondrial respiration. This implies that mitochondrial respiration is controlled at the cytochrome oxidase reaction and that oxidative phosphorylation in intact tissue is tightly coupled irrespective of thyroid state. It is concluded that thyroid hormone causes an increase in the mitochondrial mass, mitochondrial cytochrome content, and respiratory rate, and consequently expands the capacity of oxidative metabolism without an uncoupling effect on oxidative phosphorylation.

scholarly journals Protein composition and function of red and white skeletal muscle mitochondria

2011 ◽  
Vol 300 (6) ◽  
pp. C1280-C1290 ◽  
Author(s):  
Brian Glancy ◽  
Robert S. Balaban
Keyword(s):  
Skeletal Muscle ◽  
Mitochondrial Protein ◽  
Protein Composition ◽  
Metabolic Demand ◽  
Absolute Quantitation ◽  
Itraq Analysis ◽  
Palmitoyl Carnitine ◽  
Protein Contamination ◽  
Isobaric Tag ◽  
And Function

Red and white muscles are faced with very different energetic demands. However, it is unclear whether relative mitochondrial protein expression is different between muscle types. Mitochondria from red and white porcine skeletal muscle were isolated with a Percoll gradient. Differences in protein composition were determined using blue native (BN)-PAGE, two-dimensional differential in gel electrophoresis (2D DIGE), optical spectroscopy, and isobaric tag for relative and absolute quantitation (iTRAQ). Complex IV and V activities were compared using BN-PAGE in-gel activity assays, and maximal mitochondrial respiration rates were assessed using pyruvate (P) + malate (M), glutamate (G) + M, and palmitoyl-carnitine (PC) + M. Without the Percoll step, major cytosolic protein contamination was noted for white mitochondria. Upon removal of contamination, very few protein differences were observed between red and white mitochondria. BN-PAGE showed no differences in the subunit composition of Complexes I–V or the activities of Complexes IV and V. iTRAQ analysis detected 358 mitochondrial proteins, 69 statistically different. Physiological significance may be lower: at a 25% difference, 48 proteins were detected; at 50%, 14 proteins were detected; and 3 proteins were detected at a 100%. Thus any changes could be argued to be physiologically modest. One area of difference was fat metabolism where four β-oxidation enzymes were ∼25% higher in red mitochondria. This was correlated with a 40% higher rate of PC+M oxidation in red mitochondria compared with white mitochondria with no differences in P+M and G+M oxidation. These data suggest that metabolic demand differences between red and white muscle fibers are primarily matched by the number of mitochondria and not by significant alterations in the mitochondria themselves.

Effect of 3,3′-di-iodothyronine and 3,5-di-iodothyronine on rat liver mitochondria

1993 ◽  
Vol 136 (1) ◽  
pp. 59-64 ◽  
Author(s):  
A. Lanni ◽  
M. Moreno ◽  
M. Cioffi ◽  
F. Goglia
Keyword(s):  
Cytochrome Oxidase ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Mitochondrial Protein ◽  
The Other ◽  
Rat Liver Mitochondria ◽  
Mitochondrial Activity ◽  
Mitochondrial Mass ◽  
Cytochrome Oxidase Activity ◽  
Other Hand

ABSTRACT In the present study we report that 3,3′,5-tri-iodothyronine (T3) as well as two iodothyronines (3,5-diiodothyronine (3,5-T2) and 3,3′-di-iodothyronine (3,3′-T2)) significantly influence rat liver mitochondrial activity. Liver oxidative capacity (measured as cytochrome oxidase activity/g wet tissue) in hypothyroid compared with normal rats was significantly reduced (21%, P > 0·01) and the administration of T3 and both iodothyronines restored normal values. At the mitochondrial level, treatment with T3 stimulated respiratory activity (state 4 and state 3) and did not influence cytochrome oxidase activity. On the other hand, both the mitochondrial respiratory rate and specific cytochrome oxidase activity significantly increased in hypothyroid animals after treatment with 3,3′-T2 or 3,5-T2 (about 50 and 40% respectively). The actions of both iodothyronines were rapid and evident by 1 h after the injection. The hepatic mitochondrial protein content which decreased in hypothyroid rats (9·6 mg/g liver compared with 14·1 in normal controls, P < 0·05) was restored by T3 injection, while neither T2 was able to restore it. Our results suggest that T3 and both iodothyronines have different mechanisms of action. T3 acts on both mitochondrial mass and activity; the action on mitochondrial activity was not exerted at the cytochrome oxidase complex level. The action of the iodothyronines, on the other hand, is exerted directly on the cytochrome oxidase complex without any noticeable action on the mitochondrial mass. Journal of Endocrinology (1993) 136, 59–64

scholarly journals An additional acidic residue in the membrane portion of the b-subunit of the energy-transducing adenosine triphosphatase of Escherichia coli affects both assembly and function

1984 ◽  
Vol 221 (1) ◽  
pp. 43-51 ◽  
Author(s):  
D A Jans ◽  
A L Fimmel ◽  
L Hatch ◽  
F Gibson ◽  
G B Cox
Keyword(s):  
Escherichia Coli ◽  
Oxidative Phosphorylation ◽  
Atpase Activity ◽  
Dna Sequence ◽  
Mutant Allele ◽  
Adenosine Triphosphatase ◽  
The Other ◽  
Multicopy Plasmid ◽  
B Subunit ◽  
And Function

Glycine at position 9 is replaced by aspartic acid in the mutant b-subunit of Escherichia coli F1F0-ATPase coded for by the uncF476 allele. The mutant b-subunit is not assembled into the membrane in haploid strains carrying the uncF476 allele, but, if the mutant allele is incorporated into a multicopy plasmid, then some assembly of the mutant b-subunit occurs. Two revertant strains were characterized, one of which (AN2030) was a full revertant, the other (AN1953) a partial revertant. DNA sequencing indicated that in strain AN2030 the uncF476 mutation had reverted to give the sequence found in the normal uncF gene. The partial-revertant strain AN1953, however, retained the DNA sequence of the uncF476 allele, and complementation analysis indicated that the second mutation may be in the uncA gene. Membranes prepared from the partial-revertant strain carried out oxidative phosphorylation, although the membranes appeared to be impermeable to protons, and the ATPase activity was sensitive to the inhibitor dicyclohexylcarbodi-imide.

Platelet Suruival and Function in Rats with Enhanced Thrombotic Tendency

1985 ◽  
Vol 54 (04) ◽  
pp. 739-743 ◽  
Author(s):  
Federica Delaini ◽  
Elisabetta Dejana ◽  
Ine Reyers ◽  
Elisa Vicenzi ◽  
Germana De Bellis Vitti ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Nephrotic Syndrome ◽  
Platelet Function ◽  
Laboratory Tests ◽  
Thrombus Formation ◽  
The Other ◽  
Mean Survival Time ◽  
The Mean ◽  
And Function ◽  
Thrombotic Tendency

SummaryWe have investigated the relevance of some laboratory tests of platelet function in predicting conditions of thrombotic tendency. For this purpose, we studied platelet survival, platelet aggregation in response to different stimuli, TxB2 and 6-keto-PGFlα production in serum of rats bearing a nephrotic syndrome induced by adriamycin. These animals show a heavy predisposition to the development of both arterial and venous thrombosis. The mean survival time was normal in nephrotic rats in comparison to controls. As to aggregation tests, a lower aggregating response was found in ADR-treated rats using ADP or collagen as stimulating agents. With arachidonic acid (AA) we observed similar aggregating responses at lower A A concentrations, whereas at higher AA concentrations a significantly lower response was found in nephrotic rats, despite their higher TxB2 production. Also TxB2 and 6-keto-PGFlα levels in serum of nephrotic rats were significantly higher than in controls. No consistent differences were found in PGI2-activity generated by vessels of control or nephrotic rats.These data show that platelet function may appear normal or even impaired in rats with a markedly increased thrombotic tendency. On the other hand, the significance of high TxB2 levels in connection with mechanisms leading to thrombus formation remains a controversial issue.

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