scholarly journals Mitochondrial and cytosolic ATP/ADP ratios in isolated hepatocytes. A comparison of the digitonin method and the non-aqueous fractionation procedure

1980 ◽  
Vol 192 (3) ◽  
pp. 951-954 ◽  
Author(s):  
S Soboll ◽  
T P M Akerboom ◽  
W D Schwenke ◽  
R Haase ◽  
H Sies
Keyword(s):  
Isolated Hepatocytes ◽  
Perfused Liver ◽  
Mitochondrial Matrix ◽  
Atp Content ◽  
Isolated Cells ◽  
Fractionation Procedure ◽  
Biochemical Difference ◽  
Methodological Artifact

The ratio of ATP content/ADP content in the mitochondrial matrix was found to be 2.07 +/- 0.21 and 2.26 +/- 0.22 as determined with six different preparations of isolated hepatocytes subfractionated with the digitonin and non-aqueous-fractionation procedures, respectively. In contrast, the mitochondrial matrix ATP/ADP determined with isolated haemoglobin-free perfused liver by using the non-aqueous-fractionation procedure was about 0.2, whereas the cytosolic values obtained with isolated cells and with the intact organ were similar. It is concluded that the relatively higher ATP/ADP ratio in the mitochondrial matrix of isolated hepatocytes represents a biochemical difference due to properties of the model rather than a methodological artifact.

scholarly journals Mitochondrial and cytosolic ATP/ADP ratios in rat liver in vivo

1981 ◽  
Vol 200 (2) ◽  
pp. 405-408 ◽  
Author(s):  
W D Schwenke ◽  
S Soboll ◽  
H J Seitz ◽  
H Sies
Keyword(s):  
Rat Liver ◽  
Oxygen Supply ◽  
Isolated Hepatocytes ◽  
Perfused Liver ◽  
Mitochondrial Matrix ◽  
Atp Content ◽  
Anaesthetized Rats

The ratio of ATP content/ADP content in livers from unanaesthetized fed rat was 0.9 in the mitochondrial matrix and 6.9 in the cytosol; the values for starved (48 h) animals were 1.0 and 5.9 respectively. The mitochondrial ratios observed in unanaesthetized animals were higher than in haemoglobin-free-perfused liver and lower than in isolated hepatocytes. Possible reasons for these differences may be related to oxygen supply and/or other factors. Further, data from anaesthetized rats with the liver exposed are given: mitochondrial ATP/ADP ratios were decreased with pentobarbital, but less so with ketamine as narcotic agent.

scholarly journals The accumulation of aspartate in the presence of ethanol in rat liver

1975 ◽  
Vol 150 (1) ◽  
pp. 41-45 ◽  
Author(s):  
M Stubbs ◽  
H A Krebs
Keyword(s):  
Rat Liver ◽  
Aspartate Aminotransferase ◽  
Isolated Hepatocytes ◽  
Perfused Liver ◽  
Isolated Cells ◽  
Isolated Rat Liver ◽  
Ammonium Lactate ◽  
Mitochondrial Aspartate Aminotransferase ◽  
Isolated Rat ◽  
Dehydrogenation Of Ethanol

1. Isolated hepatocytes were used to establish the reasons for the accumulation of aspartate, previously observed when the isolated rat liver was perfused with ethanol in the presence of alanine or ammonium lactate. 2. The isolated cells did not form aspartate when incubated with alanine and ethanol, but much aspartate was formed on incubation with ammonium lactate and ethanol. 3. Urea was the main nitrogenous product on incubation with alanine, in contrast with the perfused liver, where major quantities of NH4+ are also formed. When the formation of urea was nullified by the addition of urease, alanine plus ethanol caused aspartate formation, indicating that aspartate formation depends on the presence of critical concentrations of NH4+. 4. The accumulated aspartate was present in the cytosol. Ethanol halved the content of 2-oxoglutarate in the cytosol and more than trebled that of glutamate in the mitochondria. 5. The findings support the assumption that 2-oxoglutarate formed by the mitochondrial aspartate aminotransferase is not translocated to the cytosol in the presence of ethanol and NH4+, because it is rapidly converted into glutamate, the dehydrogenation of ethanol providing the required NADH. Aspartate, however, is translocated to the cytosol and accumulates there because of the lack of stoicheiometric amounts of oxoglutarate.

Attenuation of glycogenolytic action of activin A in intact rat liver

1995 ◽  
Vol 269 (5) ◽  
pp. E846-E851
Author(s):  
I. Kojima ◽  
R. Nobusawa ◽  
Y. Q. Zhang ◽  
N. Sekine ◽  
T. Mine ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Inositol Phosphates ◽  
Liver Perfusion ◽  
Glucose Production ◽  
Isolated Hepatocytes ◽  
Inhibitory Effect ◽  
Activin A ◽  
Perfused Liver ◽  
Isolated Cells ◽  
Protein Factor

Activin A stimulates glucose production by causing glycogenolysis in isolated hepatocytes. To determine the physiological significance of this effect, we examined the effect of activin A on glucose production in the perfused liver. Unlike the effect in isolated cells, activin A did not enhance glucose production nor did it cause radiocalcium efflux in the perfused liver. There was no effect of activin A in the liver perfused in the opposite direction. Although activin A did not promote glucose production, it was recovered from the hepatic vein in a bioactive form. When liver perfusion was performed in partially hepatectomized rats, activin A increased radiocalcium efflux. In isolated hepatocytes, activin A increased inositol phosphates, and the effect of activin A was attenuated by the plasma membrane fraction of hepatocytes. The inhibitory effect of the plasma membrane was abolished by digestion of the membrane with trypsin. These results indicate that the effect of activin A on glucose production is attenuated in the intact liver and that a protein factor(s) in plasma membrane may be involved in the inhibition.

HUMAN HEPATOCYTES CONTAIN HIGH MOLECULAR WEIGHT POLYPEPTIDES OF FACTOR VIII

1987 ◽  
Author(s):  
J Ingerslev ◽  
B Sloth Christiansen ◽  
A Bukh ◽  
S Stenbjerg ◽  
T Munck Jørgensen ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Polyclonal Antibodies ◽  
Plasma Source ◽  
Isolated Hepatocytes ◽  
Human Hepatocytes ◽  
Isolated Cells ◽  
Left Liver Lobe ◽  
Viable Cells ◽  
A Cell

Human hepatocytes were isolated by the two-step collagenase technique applied on distal left liver lobe. Homogenous and large cells were isolated revealing hepatocyte characteristics by light-microscopy. Hepatocytes were washed repeatedly in albumine buffer (5%), resuspended in the same buffer and sonicated using a cell density of 0.75 × 106 cells/ml. In some cases cells were separated from non-viable cells by flotation on a linear Percoll gradient. Supernate material after sonication was subjected to ELISA for VIII:Ag using human antibodies and vWf:Ag by polyclonal antibodies. Freshly isolated cells contained at least 0.25 IU/ 0.75 × 106 hepatocytes, whereas the vWf:Ag was below 0.01 IU/ 0.75 × 106 cells. The material obtained from sonication was further studied using fast protein liquid chromatography by Mono-Q HR 5/5 revealing a single peak of VIII: Ag eluting in the same position as the high molecular weight polypeptides of VIII :Ag of high purity FVIII derived from the plasma source. Isolated hepatocytes also were cultivated at 37°C in medium RPMI 1640 supplemented with Ultroser G (4%), glutamine and antibiotics. Cells secreted increasing quantities of albumin, fitrinogpn and protease-inhibitors. The supernatants also contained VIII: Ag in quantities ranging from 0.04 - 0.17 IU/ml after 24 hours, but no further secretion was observed. No vWf: Ag could be detected. Cells harvested and sonicated after 30 hours of culture only contained 0.04 IU/ 0.75 × 106 cells. Our results shows, that VIII :Ag is present in freshly isolated human hepatocytes and that only traces of vWf:Ag is found. A hepatocyte site of production of VIII is speculated. These very preliminary findings do not permit conclusions concerning active synthesis of VIII in hepatocytes. Further studies are underway.

scholarly journals Interactions of dietary fat and 2,5-anhydro-d-mannitol on energy metabolism in isolated rat hepatocytes

2002 ◽  
Vol 282 (3) ◽  
pp. R715-R720 ◽  
Author(s):  
Hong Ji ◽  
Grazyna Graczyk-Milbrandt ◽  
Mary D. Osbakken ◽  
Mark I. Friedman
Keyword(s):  
Oxygen Consumption ◽  
Rat Hepatocytes ◽  
Isolated Hepatocytes ◽  
Metabolic Effects ◽  
Atp Content ◽  
Isolated Rat Hepatocytes ◽  
Palmitate Oxidation ◽  
Low Carbohydrate ◽  
Lower Oxygen ◽  
Hepatocyte Metabolism

The fructose analog 2,5-anhydro-d-mannitol (2,5-AM) stimulates feeding in rats by reducing ATP content in the liver. These behavioral and metabolic effects occur with rats fed a high-carbohydrate/low-fat (HC/LF) diet, but they are prevented or attenuated when the animals eat high-fat/low-carbohydrate (HF/LC) food. To examine the metabolic bases for this effect of diet, we assessed the actions of 2,5-AM on ATP content, oxygen consumption, and substrate oxidation in isolated hepatocytes from rats fed one of the two diets. Compared with cells from rats fed the HC/LF diet (“HC/LF” cells), cells from rats fed the HF/LC diet (“HF/LC” cells) had similar ATP contents but lower oxygen consumption, decreased fructose, and increased palmitate oxidation. 2,5-AM did not decrease ATP content or oxygen consumption in HF/LC cells as much as it did in HC/LF hepatocytes, and it only affected fructose and palmitate oxidation in HC/LF cells.31P-NMR spectroscopy indicated that differences in phosphate trapping accounted for differences in depletion of ATP by 2,5-AM. These results suggest that intake of the HF/LC diet prevents the eating response and attenuates the decline in liver ATP by shifting hepatocyte metabolism to favor fat over carbohydrate as an energy-yielding substrate.

scholarly journals Polyribosomes in isolated liver cells. Preparative procedures, effects of incubation and correlation with protein synthesis

1980 ◽  
Vol 186 (1) ◽  
pp. 35-45 ◽  
Author(s):  
A J Dickson ◽  
C I Pogson
Keyword(s):  
Protein Synthesis ◽  
Rat Liver ◽  
Isolated Hepatocytes ◽  
Liver Cells ◽  
Liver Protein ◽  
Isolated Cells ◽  
Isolated Liver Cells ◽  
Rat Liver Cells ◽  
Isolated Liver

Methods have been derived which permit the isolation of undergraded polyribosomes from isolated rat liver cells. Under the conditions used the polyribosome profile of hepatocytes immediately after isolation was essentially identical with that from intact liver. However, during incubation of cells in complex physiological media there was a progressive dissociation of polyribosomes. The addition of a variety of factors that produce reaggregation of polyribosomes in rat liver in vivo did not prevent dissociation during cell incubations. Although large polyribosomes were lost most rapidly, the albumin-synthesizing capacity of isolated cells was not selectively lost when compared with total protein synthesis. The significance of these results for the use of isolated hepatocytes in the study of liver protein synthesis is discussed.

Functional Recovery of Porcine Hepatocytes after Hypothermic or Cryogenic Preservation for Liver Support Systems

1997 ◽  
Vol 6 (5) ◽  
pp. 447-454 ◽  
Author(s):  
Sharda Naik ◽  
Henry A. Santangini ◽  
Donna M. Trenkler ◽  
Claudy J.P. Mullon ◽  
Barry A. Solomon ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Culture Media ◽  
Cost Effective ◽  
Isolated Hepatocytes ◽  
Specific Cell ◽  
Isolated Cells ◽  
Liver Support ◽  
C Storage ◽  
Liver Assist Devices ◽  
Porcine Hepatocytes

The provision of an immediate supply of isolated porcine hepatocytes for artificial liver support requires preservation techniques that will allow maintenance of cell viability and detoxification functions. By means of a simple and cost-effective cryopreservation system, porcine hepatocytes can be available for both local and distant medical treatment facilities. Additionally, cryopreservation provides an adequate period for quality control testing to be completed prior to use of any specific cell lot. We are reporting a dual approach, namely the preservation of porcine hepatocytes, at 4°C and at −196°C in liquid nitrogen (LN2). Using a combination of cryoprotectant agents with Chee's modified Eagle's culture media (CEM), collagenase isolated hepatocytes stored at 4°C for 24 h maintained 80% of the initial diazepam metabolism measured in freshly isolated cells and nearly 100% of initial function was preserved in hepatocytes stored up to 6 mo at -196°C. University of Wisconsin solution (UW) was also tested and while adequate for 4°C storage, it certainly did not match the performance of the CEM formulations for preservation of metabolic function of cells stored in liquid nitrogen. Based on our results of viability and detoxification function the combination of CEM with DMSO, polyethylene glycol and serum provided optimal protection for LN2 frozen cells. Other findings in these studies underlined the importance of the gradual introduction of DMSO in the prefreezing process, the period of osmotic equilibration, and the rapid postthaw withdrawal of this agent to minimize cytotoxic effects at these critical stages. Our freezing methodology provides the foundation for further technological developments in the cryopreservation of the large numbers of cells (billions) that are necessary for extracorporeal liver assist devices.

scholarly journals The apparent Km of ammonia for carbamoyl phosphate synthetase (ammonia) in situ

1985 ◽  
Vol 229 (1) ◽  
pp. 205-211 ◽  
Author(s):  
N S Cohen ◽  
F S Kyan ◽  
S S Kyan ◽  
C W Cheung ◽  
L Raijman
Keyword(s):  
Isolated Hepatocytes ◽  
Perfused Liver ◽  
Carbamoyl Phosphate Synthetase ◽  
Carbamoyl Phosphate ◽  
Isolated Mitochondria ◽  
Regulation Of Synthesis

Experiments with carbamoyl phosphate synthetase (ammonia) in solution and in isolated mitochondria are reported which show the following. NH3 rather than NH4+ is the substrate of the enzyme. The apparent Km of NH3 for the purified enzyme is about 38 microM. The apparent Km for NH3 measured in intact isolated mitochondria is about 13 microM. This value was obtained for both coupled and uncoupled mitochondria and was unchanged when the rate of carbamoyl phosphate synthesis was increased 2-fold by incubating uncoupled mitochondria in the presence of 5 mM-N-acetylglutamate. According to the literature, the concentration of NH3 in liver is well below the measured apparent Km. On the basis of this and previous work we conclude that, quantitatively, changes in liver [NH3] and [ornithine] are likely to be the most important factors in the fast regulation of synthesis of carbamoyl phosphate and urea. This conclusion is consistent with all available evidence obtained with isolated mitochondria, isolated hepatocytes, perfused liver and whole animals.

scholarly journals Delayed restoration of Mg2+ content and transport in liver cells following ethanol withdrawal

2009 ◽  
Vol 297 (4) ◽  
pp. G621-G631 ◽  
Author(s):  
Lisa M. Torres ◽  
Christie Cefaratti ◽  
Liliana Berti-Mattera ◽  
Andrea Romani
Keyword(s):  
Plasma Membrane ◽  
Membrane Vesicles ◽  
Isolated Hepatocytes ◽  
Liver Cells ◽  
Ethanol Withdrawal ◽  
Adrenergic Stimulation ◽  
Plasma Membrane Vesicles ◽  
Isolated Cells ◽  
Intact Cells

Liver cells from rats chronically fed a Lieber-De Carli diet for 3 wk presented a marked decreased in tissue Mg2+ content and an inability to extrude Mg2+ into the extracellular compartment upon stimulation with catecholamine, isoproterenol, or cell-permeant cAMP analogs. This defect in Mg2+ extrusion was observed in both intact cells and purified liver plasma membrane vesicles. Inhibition of adrenergic or cAMP-mediated Mg2+ extrusion was also observed in freshly isolated hepatocytes from control rats incubated acutely in vitro with varying doses of ethanol (EtOH) for 8 min. In this model, however, the defect in Mg2+ extrusion was observed in intact cells but not in plasma membrane vesicles. In the chronic model, upon removal of EtOH from the diet hepatic Mg2+ content and extrusion required ∼10 days to return to normal level both in isolated cells and plasma membrane vesicles. In hepatocytes acutely treated with EtOH for 8 min, more than 60 min were necessary for Mg2+ content and extrusion to recover and return to the level observed in EtOH-untreated cells. Taken together, these data suggest that in the acute model the defect in Mg2+ extrusion is the result of a limited refilling of the cellular compartment(s) from which Mg2+ is mobilized upon adrenergic stimulation rather than a mere defect in adrenergic cellular signaling. The chronic EtOH model, instead, presents a transient but selective defect of the Mg2+ extrusion mechanisms in addition to the limited refilling of the cellular compartments.

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