scholarly journals Biphasic effect of acute ethanol administration on rat liver tyrosine-2-oxoglutarate aminotransferase activity

1980 ◽  
Vol 186 (3) ◽  
pp. 755-761 ◽  
Author(s):  
A A B Badawy ◽  
B M Snape ◽  
M Evans
Keyword(s):  
Enzyme Activity ◽  
Rat Liver ◽  
Actinomycin D ◽  
Tyrosine Aminotransferase ◽  
Ethanol Metabolism ◽  
Ethanol Administration ◽  
Aminotransferase Activity ◽  
Biphasic Effect ◽  
Initial Decrease ◽  
Acute Ethanol

1. Acute ethanol administration causes a biphasic change in rat liver tyrosine aminotransferase activity. 2. The initial decrease is significant with a 200 mg/kg dose of ethanol, is prevented by adrenoceptor-blocking agnets and by reserpine, but not by inhibitors of ethanol metabolism, and exhibits many of the characteristics of the inhibition caused by noradrenaline. 3. The subsequent enhancement of the enzyme activity by ethanol is not associated with stabilization of the enzyme, but is sensitive to actinomycin D and cycloheximide. 4. It is suggested that the initial decrease in aminotransferase activity is caused by the release of catecholamines, whereas the subsequent enhancement may be related to the release of glucocorticoids.

Effects of acute ethanol administration on tyrosine aminotransferase activity

FEBS Letters ◽  
1979 ◽  
Vol 105 (2) ◽  
pp. 205-208 ◽  
Author(s):  
Catherine Ribiere ◽  
Hélène Rouach ◽  
Joseph Nordmann ◽  
Roger Nordmann
Keyword(s):  
Tyrosine Aminotransferase ◽  
Ethanol Administration ◽  
Aminotransferase Activity ◽  
Acute Ethanol

scholarly journals Rat liver tyrosine aminotransferase activity and induction by dexamethasone upon cadmium intoxication

2003 ◽  
Vol 55 (1-2) ◽  
pp. 3-7 ◽  
Author(s):  
Jadranka Dundjerski ◽  
Jelena Predic ◽  
Aleksandra Cvoro ◽  
Gordana Matic
Keyword(s):  
Enzyme Activity ◽  
Gene Transcription ◽  
Rat Liver ◽  
Tyrosine Aminotransferase ◽  
Aminotransferase Activity ◽  
Liver Cytosol ◽  
Cadmium Intoxication ◽  
Rat Liver Cytosol

This study was focused on Cd effects on basal and dexamethasone-induced tyrosine aminotransferase (TAT) activity in the rat liver cytosol. Cadmium (Cd), applied in the dose of 2 mg/kg b.w., stimulated both TAT activity and its induction by dexamethasone, inducing the most prominent alterations 24 h after administration. Doses lower than 2 mg Cd/kg b.w. were ineffective while the higher ones (3 and 4 mg Cd/kg b.w) led to the changes similar to those reached by 2 mg Cd/kg. The in vitro application of different Cd concentrations to the liver cytosol rendered the enzyme activity unchanged suggesting that the metal acted at the level of TAT gene transcription.

scholarly journals The effects of salicylate on the activity of rat liver tyrosine–2-oxoglutarate aminotransferase in vitro and in vivo

1972 ◽  
Vol 126 (2) ◽  
pp. 347-350 ◽  
Author(s):  
A. A.-B. Badawy
Keyword(s):  
Rat Liver ◽  
Pyridoxal Phosphate ◽  
Actinomycin D ◽  
Sodium Salicylate ◽  
Intraperitoneal Administration ◽  
Tyrosine Aminotransferase ◽  
Major Effect ◽  
Endogenous Activity

1. Salicylate, in concentrations of 0.25mm and above, enhances the basal activity of tyrosine–2-oxoglutarate aminotransferase in homogenates of rat liver incubated in the absence of added pyridoxal 5′-phosphate (endogenous activity). The effect is decreased by increasing the concentration of the cofactor. 2. The intraperitoneal administration of sodium salicylate enhances the activity of rat liver tyrosine aminotransferase; the major effect during the first hour being on the enzyme in the absence of added pyridoxal phosphate. Actinomycin D prevents the induction of the enzyme by cortisol and tryptophan. Induction by pyridoxine or salicylate is 50% inhibited by actinomycin D. The effects of the injections of various combinations of cortisol, pyridoxine and salicylate were also studied in the absence or presence of actinomycin D. 3. It is suggested that salicylate induces rat liver tyrosine aminotransferase by displacing its protein-bound cofactor and that a cofactor-type induction of the hepatic enzyme occurs in pyridoxine-treated rats.

scholarly journals The role of free serum tryptophan in the biphasic effect of acute ethanol administration on the concentrations of rat brain tryptophan, 5-hydroxytryptamine and 5-hydroxyindol-3-ylacetic acid

1976 ◽  
Vol 160 (2) ◽  
pp. 315-324 ◽  
Author(s):  
A A Badawy ◽  
M Evans
Keyword(s):  
Rat Brain ◽  
Tryptophan Metabolism ◽  
Ethanol Administration ◽  
Acute Administration ◽  
Free Tryptophan ◽  
Biphasic Effect ◽  
Acute Ethanol ◽  
Comparison Of The Results ◽  
Ylacetic Acid

1. Acute administration of ethanol exerts a biphasic effect on the concentrations of rat brain tryptophan, 5-hydroxytryptamine and 5-hydroxyindol-3-ylacetic acid. Both effects are associated with corresponding changes in the availability of circulating free tryptophan. 2. The initial increases in the above concentrations are prevented by ergotamine, are unaltered by allopurinol and are potentiated by theophylline, whereas the later decreases are prevented by both ergotamine and allopurinol. 3. It is suggested that the initial enhancement by ethanol of brain tryptophan metabolism is caused by catecholamine-mediated lipolysis followed by displacement of protein-bound serum tryptophan, whereas the activation of liver tryptophaan pyrrolase, which is produced by the same mechanism, leads to the later decreases in the brain concentrations of tryptophan and its metabolites. 4. The initial effects of ethanol can be reproduced by an equicaloric dose of sucrose, and a comparison of the two treatments alone could therefore be misleading. 5. The effects of ethanol on liver and brain tryptophan metabolism have also been examined in mice, and a comparison of the results with those previously reported suggests that the ethanol effects are strain-dependent.

Hepatic metabolism and enzyme activity in acute ethanol administration

1967 ◽  
Vol 16 (9) ◽  
pp. 1813-1819 ◽  
Author(s):  
P. Nelson ◽  
W.C. Tan ◽  
S.R. Wagle ◽  
J. Ashmore
Keyword(s):  
Enzyme Activity ◽  
Hepatic Metabolism ◽  
Ethanol Administration ◽  
Acute Ethanol

Transglutaminase activity in rat liver after acute ethanol administration

1995 ◽  
Vol 1245 (3) ◽  
pp. 371-375 ◽  
Author(s):  
Angela Sessa ◽  
Patrizia Tunici ◽  
Edoardo Perilli ◽  
Antonio Perin
Keyword(s):  
Rat Liver ◽  
Ethanol Administration ◽  
Transglutaminase Activity ◽  
Acute Ethanol

scholarly journals Tyrosine aminotransferase induction in hepatocytes cultured from rat foetuses treated with dexamethasone in utero

1979 ◽  
Vol 180 (3) ◽  
pp. 545-549 ◽  
Author(s):  
G C T Yeoh ◽  
T Arbuckle ◽  
I T Oliver
Keyword(s):  
Culture Medium ◽  
Actinomycin D ◽  
Tyrosine Aminotransferase ◽  
In Utero ◽  
Aminotransferase Activity ◽  
Foetal Liver ◽  
Translational Block ◽  
Cells Cultured ◽  
Specific Mrna

1. The administration of dexamethasone to foetal rats in utero does not result in the appearance of specific tyrosine aminotransferase activity even after 24 h. 2. When foetal hepatocytes are cultured in vitro from animals treated in utero with dexamethasone, significantly higher activities of specific tyrosine aminotransferase are found than in untreated controls. 3. Dexamethasone in vitro induces specific tyrosine aminotransferase in cells cultured from control animals and the effect is maximal at 10 nM in the culture medium. 4. Actinomycin D at 0.2 microgram/ml in the culture medium completely prevents the induction of activity in vitro. 5. In cultures established from animals treated with dexamethasone in utero, the increase in specific tyrosine aminotransferase activity over the control cultures is only marginally decreased in the presence of actinomycin D. 6. The results can be interpreted to mean that dexamethasone in utero stimulates the transcription of enzyme-specific mRNA, which is not rranslated until a translational block in the foetal liver is removed by the conditions of culture in vitro.

scholarly journals Effects of acute ethanol administration on rat liver 5-aminolaevulinate synthase activity

1989 ◽  
Vol 262 (2) ◽  
pp. 491-496 ◽  
Author(s):  
A A B Badawy ◽  
C J Morgan ◽  
N R Davis
Keyword(s):  
Alcohol Dehydrogenase ◽  
Rat Liver ◽  
Intraperitoneal Administration ◽  
Reciprocal Relationship ◽  
Ethanol Administration ◽  
Simultaneous Increase ◽  
Acute Ethanol ◽  
Tryptophan Pyrrolase ◽  
Dose Dependent Decrease ◽  
Dose Dependent

1. Liver 5-aminolaevulinate (ALA) synthase activity of 24 h-starved rats is maximally increased at 4 h after intraperitoneal administration of a 1.6 g/kg body wt. dose of ethanol. Larger doses cause a dose-dependent decrease in the extent of this stimulation, exhibiting a reciprocal relationship with an elevation of hepatic haem concentration, as suggested by the simultaneous increase in the haem saturation of tryptophan pyrrolase. 2. ALA synthase induction by ethanol is abolished if the above increase in pyrrolase saturation with haem is enhanced by theophylline, but is potentiated when the increase in the haem saturation is inhibited by anti-lipolytic agents. 3. ALA synthase induction by ethanol is also inhibited by inhibitors of alcohol dehydrogenase and aldehyde dehydrogenase. Acetaldehyde and acetate are, however, not responsible; they both decrease ALA synthase activity and increase the haem saturation of tryptophan pyrrolase. These latter effects of acetaldehyde are not mediated by acetate. 4. ALA synthase activity is also stimulated by succinate, which, however, also increases the haem saturation of tryptophan pyrrolase. 5. Ethanol does not influence the rate of ALA synthase degradation. 6. It is suggested that ethanol increases rat liver ALA synthase activity as a result of its own metabolism by the alcohol dehydrogenase-dependent pathway by a mechanism not involving decreased degradation of the former enzyme or the participation of the metabolites acetaldehyde and acetate.

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