scholarly journals Measurement of the absolute rates of cholesterol biosynthesis in isolated rat liver cells

1977 ◽  
Vol 162 (2) ◽  
pp. 321-330 ◽  
Author(s):  
G F Gibbons ◽  
C R Pullinger
Keyword(s):  
Cholesterol Biosynthesis ◽  
Specific Radioactivity ◽  
Liver Cells ◽  
Electron Capture Detection ◽  
High Electron ◽  
Accurate Assessment ◽  
Isolated Liver Cells ◽  
Rat Liver Cells ◽  
Isolated Liver ◽  
Enol Ester

Triparanol [2-(4-chlorophenyl)-1-(4-diethylaminoethoxyphenyl)-1-p-tolylethanol] at a concentration of 2 micronm has no effect on the overall conversion of [2=14C]acetate into C27 sterols by isolated liver cells. In the presence of triparanol, however, the formation of radioactive cholesterol is inhibited by 85-90% and the balance of radioactivity appears in the C27 sterol desmosterol (cholesta-5,24-dien-3beta-ol). The very small weights of desmosterol which accumulate under these conditions were, as a routine, quantitatively converted into the heptafluorobutyrate 3-enol ester of cholesta-4,24-dien-3-one. This derivative has a high electron-capturing capability, a property that enables extremely small quantities (less than 0.25pmol) of the material to be accurately measured by gas chromatography with electron-capture detection. Measurements of the mass and specific radioactivity of the newly biosynthesized desmosterol formed in the presence of triparanol provides an accurate assessment of the amount of cholesterol that would be synthesized by the liver cells in the absence of the drug.

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.

scholarly journals Rate-limiting factors in the oxidation of ethanol by isolated rat liver cells

1975 ◽  
Vol 150 (2) ◽  
pp. 205-209 ◽  
Author(s):  
A J Meijer ◽  
G M van Woerkom ◽  
J R Williamson ◽  
J M Tager
Keyword(s):  
Hydrogen Transfer ◽  
Liver Cells ◽  
Limiting Factors ◽  
Cell Content ◽  
Isolated Liver Cells ◽  
Rat Liver Cells ◽  
Rate Limiting ◽  
Isolated Liver ◽  
Oxidation Of Ethanol ◽  
Reducing Equivalents

The oxidation of ethanol by isolated liver cells from starved rats is limited by the rate of removal of reducing equivalents generated in the cytosol by alcohol dehydrogenase. Evidence is presented suggesting that, in these cells, transfer of reducing equivalents from the cytosol to the mitochondria is regulated by the intracellular concentrations of the intermediates of the malate-aspartate and glycerol 3-phosphate cycles, as well as by flux through the respiratory chain. In liver cells isolated from fed rats, the availability of substrate increased the cell content of intermediates of the hydrogen-transfer cycles, and enhanced ethanol uptake. Under these conditions, ethanol consumption is limited by the availability of ADP for oxidative phosphorylation.

scholarly journals Effect of 4-hydroxypyrazole on tryptophan and formate metabolism in isolated rat liver cells

1982 ◽  
Vol 204 (1) ◽  
pp. 307-312 ◽  
Author(s):  
J S Cook ◽  
C I Pogson
Keyword(s):  
Liver Cells ◽  
Isolated Rat Liver ◽  
Formate Oxidation ◽  
Isolated Liver Cells ◽  
Rat Liver Cells ◽  
Isolated Liver ◽  
Isolated Rat ◽  
Formate Metabolism ◽  
In Cells

1. 4-Hydroxypyrazole inhibits flux through tryptophan 2.3-dioxygenase in cells. The inhibition is apparently non-competitive with Ki = 0.15 mM. 2. Hydroxypyrazole inhibits the oxidation of formate to CO2 in liver cells. 3. Glycollate, which generates H2O2, stimulates formate oxidation. This process is inhibited by 4-hydroxypyrazole. 4. Methionine stimulates formate oxidation in cells and this stimulation is insensitive to 4-hydroxypyrazole. 5. It is concluded that, in freshly isolated liver cells, formate oxidation proceeds by a pathway involving catalase. In vivo, or when methionine is added to cell incubations, the pathway of oxidation involves tetrahydrofolate, and is insensitive to catalase inhibitors. 6. Methionine at physiological concentrations inhibits the activity of tryptophan 2,3-dioxygenase in isolated liver cells.

scholarly journals Induction of cadmium-thionein in isolated rat liver cells

1978 ◽  
Vol 170 (2) ◽  
pp. 219-225 ◽  
Author(s):  
H A Hidalgo ◽  
V Koppa ◽  
S E Bryan
Keyword(s):  
Actinomycin D ◽  
De Novo ◽  
Cadmium Concentration ◽  
Deae Cellulose ◽  
Liver Cells ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Isolated Liver Cells ◽  
Rat Liver Cells ◽  
Isolated Liver

The uptake of cadmium by isolated liver cells was linearly related to the cadmium concentration to which the cells were exposed in the medium. Cadmium-treated cells synthesized proteins de novo with the characteristics of cadmium-thionein induced in the liver of cadmium-treated animals. Thionein from liver cells incorporated cadmium and [35S]cysteine, had a Ve/Vo (Sephadex G-50) of 1.8-1.9, and was separated into two subfractions by DEAE-cellulose ion-exchange chromatography. Cycloheximide and actinomycin D when added after a cadmium exposure prevented the synthesis of thionein. However, addition of actinomycin D after synthesis had started only decreased the total amount of thionein synthesized. The concentration of cadmium to which the cells were exposed affected the amount of cadmium-thionein synthesized in 6h. The maximum response occurred when cells were exposed to 0.5 microgram of cadmium/ml; at higher metal concentrations the total amount of cadmium-thionein synthesized declined. The system described in the present paper can be used to study the mode of metal toxicity and the mechanism of cadmium-thionein synthesis.

Relationship between the resting metabolic rate and hepatic metabolism in rats: effect of hyperthyroidism and fasting for 24 hours

1992 ◽  
Vol 135 (1) ◽  
pp. 45-51 ◽  
Author(s):  
S. Iossa ◽  
G. Liverini ◽  
A. Barletta
Keyword(s):  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
Hepatic Metabolism ◽  
Isolated Hepatocytes ◽  
Liver Cells ◽  
Isolated Liver Cells ◽  
Rat Liver Cells ◽  
The Relationship ◽  
Isolated Liver

ABSTRACT We have examined the relationship between the changes in resting metabolic rate (RMR) and those in hepatic metabolism induced by hyperthyroidism and fasting for 24 h. We found that hyperthyroidism induced a significant increase in RMR, while fasting for 24 h reduced RMR in euthyroid but not in hyperthyroid rats. We have also measured oxygen consumption in isolated hepatocytes from euthyroid and hyperthyroid rats, fed or fasted for 24 h. Hyperthyroidism induced an increase in oxygen consumption in rat liver cells; fasting for 24 h increased respiratory rates in isolated liver cells from euthyroid but not from hyperthyroid rats. The findings showed that hyperthyroidism and fasting for 24 h have opposite effects on RMR but similar effects on hepatic metabolism. The results also indicated that the increase in RMR found in hyperthyroid rats is partly due to an increase in hepatic metabolism, while no correlation exists between variations in resting and hepatic metabolism induced by 24-h fasting. Journal of Endocrinology (1992) 135, 45–51

scholarly journals Arachidonic acid synthesis studied in isolated liver cells

FEBS Letters ◽  
1981 ◽  
Vol 133 (2) ◽  
pp. 201-204 ◽  
Author(s):  
B.O. Christophersen ◽  
Jon Norseth
Keyword(s):  
Arachidonic Acid ◽  
Acid Synthesis ◽  
Liver Cells ◽  
Isolated Liver Cells ◽  
Isolated Liver

Decreased glucagon-stimulated cyclic AMP production by isolated liver cells of rats with type 2 diabetes

1983 ◽  
Vol 32 (1) ◽  
pp. 13-26 ◽  
Author(s):  
Bernard Portha ◽  
Hilda Chamras ◽  
Yvonne Broer ◽  
Luc Picon ◽  
Gabriel Rosselin
Keyword(s):  
Type 2 Diabetes ◽  
Cyclic Amp ◽  
Liver Cells ◽  
Isolated Liver Cells ◽  
Isolated Liver

scholarly journals Amylase in Isolated Liver Cells

1960 ◽  
Vol 235 (5) ◽  
pp. 1354-1358
Author(s):  
Robert L. McGeachin ◽  
Betty Ann Potter
Keyword(s):  
Liver Cells ◽  
Isolated Liver Cells ◽  
Isolated Liver
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