Possible Interrelationship of Ethanol Metabolism and Choline Oxidation in the Liver

1973 ◽  
Vol 51 (2) ◽  
pp. 117-120 ◽  
Author(s):  
D. J. Tuma ◽  
A. J. Barak ◽  
D. F. Schafer ◽  
M. F. Sorrell
Keyword(s):  
Alcohol Dehydrogenase ◽  
Guinea Pig ◽  
Oxidative Degradation ◽  
Oxidase Inhibitor ◽  
Choline Oxidase ◽  
Ethanol Metabolism ◽  
Choline Uptake ◽  
Perfused Liver ◽  
Ethanol Effect ◽  
Rat Experiments

Since it has been demonstrated that ethanol increases choline uptake in liver, this study was designed to determine whether this is a direct effect of ethanol or a result of ethanol metabolism. This study also sought to determine whether oxidative degradation of choline regulates choline uptake in the liver and if ethanol-induced choline uptake is effected through the action of choline oxidase.Using the isolated perfused-liver technique to study choline uptake, it was found that the addition of pyrazole, an alcohol dehydrogenase inhibitor, to the perfusate completely inhibited the effect of ethanol on choline uptake. This work suggested that ethanol metabolism is necessary to obtain the ethanol effect. Experiments with guinea pig livers, which contain very little choline oxidase, and the use of a choline oxidase inhibitor in rat experiments showed that choline uptake is partially regulated by choline oxidase. The choline oxidase inhibitor was also shown to inhibit the ethanol effect on choline uptake, suggesting that increased choline requirement due to alcohol ingestion may be the result of ethanol metabolism stimulating oxidative degradation of choline.

scholarly journals Dehydrogenase-dependent Ethanol Metabolism in Deer Mice (Peromyscus maniculatus) Lacking Cytosolic Alcohol Dehydrogenase

1989 ◽  
Vol 264 (10) ◽  
pp. 5593-5597
Author(s):  
C Norsten ◽  
T Cronholm ◽  
G Ekström ◽  
J A Handler ◽  
R G Thurman ◽  
...  
Keyword(s):  
Alcohol Dehydrogenase ◽  
Peromyscus Maniculatus ◽  
Ethanol Metabolism ◽  
Deer Mice

Role of hepatic γ-glutamyltransferase in the degradation of circulating glutathione: Studies in the intact guinea pig perfused liver

Hepatology ◽  
1990 ◽  
Vol 11 (5) ◽  
pp. 843-849 ◽  
Author(s):  
Hernan Speisky ◽  
Nick Shackel ◽  
George Varghese ◽  
Denis Wade ◽  
Yedy Israel
Keyword(s):  
Guinea Pig ◽  
Perfused Liver

scholarly journals The biosynthesis of tyramine glucuronide by liver microsomal fractions

1977 ◽  
Vol 164 (3) ◽  
pp. 529-531 ◽  
Author(s):  
K P Wong
Keyword(s):  
Monoamine Oxidase ◽  
Guinea Pig ◽  
Glucuronic Acid ◽  
Monoamine Oxidase Inhibitor ◽  
Oxidase Inhibitor ◽  
Freezing And Thawing ◽  
Monkey Liver ◽  
Specific Activities ◽  
Low Activity

Labelled tyramine glucuronide was synthesized in vitro from UDP-[14C]glucuronic acid, [14C]tyramine or [3H]tyramine. The glucuronidation was carried out at pH9.2 in the presence of a monoamine oxidase inhibitor, trans-2-phenylcyclopropylamine. The Km values for tyramine were 69 and 125 micrometer and those for UDP-glucuronic acid were 260 and 290 micrometer respectively for guinea-pig and rat liver microsomal preparatons. The specific activities of microsomal glucuronyltransferase measured in fresh hepatic preparations of guinea pig, mouse and rat were respectively 601, 251 and 235 pmol of [14C]tyramine glucuronide/min per mg of protein. Increase in activity ranged from 2- to 6-fold in preparations which were frozen and thawed once and 5.4- to 10-fold when the freezing and thawing was repeated. Rabbit liver has very low activity, and monkey liver and intestine were completely devoid of this conjugating capacity.

Elevation of Alcohol Dehydrogenase Activity in the Subclinically Scorbutic Guinea-Pig

1972 ◽  
Vol 42 (6) ◽  
pp. 781-784 ◽  
Author(s):  
Maureen O'keane ◽  
M. R. Moore ◽  
A. Goldberg
Keyword(s):  
Alcohol Dehydrogenase ◽  
Guinea Pig ◽  
Dehydrogenase Activity ◽  
Guinea Pigs ◽  
Liver Protein ◽  
Alcohol Dehydrogenase Activity ◽  
Nadh Ratio

1. Because it has been shown that a majority of alcoholics are subclinically scorbutic, the metabolism of ethanol was studied in subclinically-scorbutic guinea-pigs. 2. Hepatic alcohol dehydrogenase activity was raised maximally by ethanol within 2 days. 3. In twenty-three subclinically-scorbutic guinea-pigs fed ethanol for 2 weeks, the alcohol dehydrogenase activity (±SD) was 11·5 ± 1·2 units/g of liver protein compared with 8·6 ± 0·6 units/g of liver protein in twenty-three healthy animals fed ethanol. 4. The NAD+/NADH ratio in subclinically-scorbutic guinea-pigs and healthy guinea-pigs fed ethanol, shows that there is more NAD+ available for oxidation of alcohol in subclinically-scorbutic guinea-pigs. These results may explain the increased tolerance of alcoholics to alcohol.

Regulation of ethanol metabolism in the rat

1987 ◽  
Vol 65 (5) ◽  
pp. 458-466 ◽  
Author(s):  
S. Cheema-Dhadli ◽  
F. A. Halperin ◽  
K. Sonnenberg ◽  
V. MacMillan ◽  
M. L. Halperin
Keyword(s):  
Alcohol Dehydrogenase ◽  
Ethanol Oxidation ◽  
Maximum Velocity ◽  
Reducing Power ◽  
Ammonium Bicarbonate ◽  
Ethanol Metabolism ◽  
Urea Synthesis ◽  
Major Pathway ◽  
Nadh Generation

The purpose of these experiments was to examine the factors which regulate ethanol metabolism in vivo. Since the major pathway for ethanol removal requires flux through hepatic alcohol dehydrogenase, the activity of this enzyme was measured and found to be 2.9 μmol/(min∙g liver). Ethanol disappearance was linear for over 120 min in vivo and the blood ethanol fell 0.1 mM/min; this is equivalent to removing 20 μmol ethanol/min and would require that flux through alcohol dehydrogenase be about 60% of its measured maximum velocity. To test whether ethanol metabolism was limited by the rate of removal of one of the end products (NADH) of alcohol dehydrogenase, fluoropyruvate was infused to reoxidize hepatic NADH and to prevent NADH generation via flux through pyruvate dehydrogenase. There was no change in the rate of ethanol clearance when fluoropyruvate was metabolized. Furthermore, enhancing endogenous hepatic NADH oxidation by increasing the rate of urea synthesis (converting ammonium bicarbonate to urea) did not augment the steady-state rate of ethanol oxidation. Hence, transport of cytoplasmic reducing power from NADH into the mitochondria was not rate limiting for ethanol oxidation. In contrast, ethanol oxidation at the earliest time periods could be augmented by increasing hepatic urea synthesis.

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