l-Asparaginase effects on inhibition of protein synthesis and lowering of the glutamine content in cultured rat hepatocytes

1986 ◽  
Vol 32 (3) ◽  
pp. 235-241 ◽  
Author(s):  
Pia Villa ◽  
Monica Corada ◽  
Ivan Bartosek
Keyword(s):  
Protein Synthesis ◽  
Rat Hepatocytes ◽  
Inhibition Of Protein Synthesis ◽  
Cultured Rat Hepatocytes

scholarly journals The acylation of proteins by xenobiotic amphipathic carboxylic acids in cultured rat hepatocytes

1988 ◽  
Vol 254 (1) ◽  
pp. 39-44 ◽  
Author(s):  
R Hertz ◽  
J Bar−Tana
Keyword(s):  
Protein Synthesis ◽  
Carboxylic Acids ◽  
Mode Of Action ◽  
Biological Effects ◽  
Rat Hepatocytes ◽  
Protein Adducts ◽  
Cultured Rat Hepatocytes ◽  
Acylated Proteins ◽  
Dose Dependent ◽  
Protein Acylation

Three xenobiotic amphipathic carboxylates, namely MEDICA 16, nafenopin and bezafibrate, which differ remarkably in their hydrophobic backbones, were found to acylate membrane and cytosolic liver proteins in cultured rat hepatocytes. The acylation patterns observed were time- and dose-dependent, and the acylated residue consisted of the original xenobiotic. The acylation patterns generated by the three xenobiotic carboxylates included common proteins which were acylated by the three xenobiotics (e.g. proteins of 32, 52, 56 and 72 kDa) as well as unique proteins which were specifically acylated by the respective xenobiotics. The acylation of liver proteins by either MEDICA 16 or nafenopin remained unaffected under conditions where protein synthesis was completely inhibited by cycloheximide. Protein acylation thus offers a common mode of action of xenobiotic amphipathic carboxylates, which may, however, result in diverse xenobiotyl-protein adducts. The xenobiotyl-acylated proteins might be involved in triggering some of the biological effects exerted by xenobiotic amphipathic carboxylates employed as hypolipidaemic effectors, peroxisomal proliferators or preadipocyte convertors.

scholarly journals Homocysteine enhances the inhibitory effect of extracellular adenosine on the synthesis of proteins in isolated rat hepatocytes

1995 ◽  
Vol 310 (3) ◽  
pp. 893-896 ◽  
Author(s):  
S Tinton ◽  
P Buc-Calderon
Keyword(s):  
Protein Synthesis ◽  
Kinase Inhibitor ◽  
Adenine Nucleotides ◽  
Rat Hepatocytes ◽  
Isolated Hepatocytes ◽  
Adenosine Kinase ◽  
Isolated Rat Hepatocytes ◽  
Extracellular Adenosine ◽  
Inhibition Of Protein Synthesis ◽  
Isolated Rat

Previous work has shown that extracellular adenosine inhibits the incorporation of radiolabelled leucine into proteins in isolated rat hepatocytes [Tinton, Lefebvre, Cousin and Buc Calderon (1993) Biochim. Biophys. Acta 1176, 1-6]. In this study, we investigated whether its metabolism into adenine nucleotides, inosine or S-adenosylhomocysteine (AdoHcy) is required to induce such an impairment. Incubation of isolated hepatocytes in the presence of adenosine at 0.5 or 1 mM reduces the synthesis of proteins by about 45% after 120 min of incubation. Such an inhibition occurred without cell lysis and was not modified by adding the adenosine kinase inhibitor 5-iodotubercidin (15 microM) or the adenosine deaminase inhibitor coformycin (0.1 microM). It is therefore unlikely that the anabolic and catabolic pathways of adenosine are involved in the inhibition of protein synthesis. Adenosine (1 mM) increased the level of AdoHcy and S-adenosylmethionine by 20- and 5-fold respectively after 60 min of incubation and reduced the methylation index. These events as well as the inhibition of protein synthesis were strongly enhanced in the presence of L-homocysteine (2 mM). It is therefore concluded that the metabolism of adenosine into AdoHcy, which is known to be a potent inhibitor of cellular methylation reactions, may play an important role in the control of translation.

Amiloride blocks cell-free protein synthesis at levels attained inside cultured rat hepatocytes

1982 ◽  
Vol 108 (2) ◽  
pp. 738-745 ◽  
Author(s):  
H.L. Leffert ◽  
K.S. Koch ◽  
M. Fehlmann ◽  
W. Heiser ◽  
P.J. Lad ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Rat Hepatocytes ◽  
Free Protein ◽  
Cultured Rat Hepatocytes ◽  
Cell Free Protein Synthesis

scholarly journals Evidence that ligand formation is a mechanism underlying the maintenance of cytochrome P-450 in rat liver cell culture. Potent maintenance by metyrapone

1980 ◽  
Vol 188 (3) ◽  
pp. 937-939 ◽  
Author(s):  
A J Paine ◽  
P Villa ◽  
L J Hockin
Keyword(s):  
Cell Culture ◽  
Protein Synthesis ◽  
Rat Liver ◽  
Liver Cell ◽  
Rat Hepatocytes ◽  
Liver Cell Culture ◽  
Substituted Pyridines ◽  
Cultured Rat Hepatocytes ◽  
Highly Correlated ◽  
Cytochrome P 450

The loss of cytochrome P-450 in cultured rat hepatocytes can be prevented by substituted pyridines, especially isonicotinamide, 3-hydroxypyridine and metyrapone. The effect of these compounds is independent of protein synthesis, suggesting that they maintain pre-existing cytochrome P-450. The efficiency of pyridines at maintaining cytochrome P-450 in hepatocyte culture is highly correlated with their ability to bind to this cytochrome, suggesting that ligand formation with cytochrome P-450 prevents its accelerated turnover in liver cell culture.

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