Stomach Alcohol Research Articles

Analysis of fractional blood alcohol model with composite fractional derivative

Abstract The present article deals with certain new and interesting features of fractional blood alcohol model associated with powerful Hilfer fractional operator. The solution of the model depends on three parameters such as (i) the initial concentration of alcohol in stomach after ingestion (ii) the rate of alcohol absorption into the blood stream (ii) the rate at which the alcohol is metabolized by the liver. By employing Sumudu transform algorithm the analytic results of the concentration of alcohol in stomach and the concentration of alcohol in the blood are analyzed. The general solution of concentration of alcohol in stomach and the concentration of alcohol in the blood are demonstrated in the form of extended Mittag-Leffler function. The effect of fractional parameter on concentration of alcohol in stomach and the concentration of alcohol in the blood are shown in graphical form. The comparative study for both the concentrations shows the new features of composite fractional derivative in the discussed model. The discussed fractional blood alcohol model yields important and useful results to interpolate new information in the direction of medical environment.

Gender difference in enzymes related with alcohol consumption in hamster, an avid consumer of alcohol

Syrian golden hamster ( Mesocricetus auratus) is extraordinary among laboratory rodents in its ability to drink alcohol. After being given a free choice between 15% ethanol and water for 5 days, both male and female hamsters derived at least 85% of the fluid intake from the ethanol solution. Analysis of the alcohol-metabolizing enzymes in alcohol-naı̈ve hamsters showed that the male had a higher activity of 57%, 58% and 34% in stomach alcohol dehydrogenase, liver cytochrome P450 1A2 and liver aldehyde dehydrogenase, respectively, compared with the female. The activity of lung angiotensin-converting enzyme, which influence fluid intake, was twofold higher in the male. After 4 weeks of ethanol consumption, the activities of the hepatic alcohol-metabolizing enzymes remained unchanged except cytochrome P450 2E1 which increased 42% and 88% in male and female hamsters, respectively. A reduction of ∼80% in the activity of cytochrome P450 1A2 was observed in both genders. The activities of several other cytochrome P450 enzymes were also decreased. Although ethanol consumption did not increase plasma aminotransferase levels, it caused a significant increase in liver weight in female, but not male hamsters.

Human stomach alcohol and aldehyde dehydrogenases: Comparison of expression pattern and activities in alimentary tract

BACKGROUND & AIMS: Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are the major enzymes responsible for ethanol metabolism in humans. The human stomach has been documented to be involved in the metabolism of first-passed alcohol. The aim of this study was to determine ethanol-metabolizing activities in the stomach with regard to sex, age, enzyme pattern, and polymorphism.METHODS: A total of 209 surgical gastric mucosal specimens were investigated. The expression patterns of ADH and ALDH were identified by isoelectric focusing, and the activities were assayed spectrophotometrically.RESULTS: At 33 or 500 mmol/L ethanol, pH 7.5, the activities in the ADH3 1-1 phenotypic and mu-ADH-expressing mucosal specimens were significantly greater than that in the ADH3 1-2 phenotypic and mu-ADH absent mucosal specimens, respectively. The activities of the ALDH2- inactive phenotypes were significantly lower than that of the ALDH2- active phenotypes at 200 micromol/L acetaldehyde. The gastric ADH and ALDH activities were not significantly different between men and women with respect to age and genetic polymorphism.CONCLUSIONS: The stomach may contribute only a small portion of the alcohol metabolism observed in humans, and the liver may be the major site for first-pass metabolism. Differential expression patterns of ADH and ALDH in the alimentary tract suggest that different vulnerabilities to ethanol- induced mucosal injury may exist.(Gastroenterology 1997 Mar;112(3):766-75)

Expression, activities, and kinetic mechanism of human stomach alcohol dehydrogenase. Inference for first-pass metabolism of ethanol in mammals.

Alcohol dehydrogenase (ADH) is a dimeric molecule containing two zinc atoms per subunit, one for catalytic and the other for structural functions (Eklund and Branden, 1987; Hurley et al., 1994). Human ADH constitutes a complex family. Seven genes have thus far been identified. ADH 1 through ADH 5 and ADH 7 encode α, β, γ, π, χ and μ (or denoted σ) polypeptides, respectively (Smith, 1986; Yoshida et al., 1991; Jornvall and Hoog, 1995). The ADH 6-encoding subunit has not yet been designated a Greek letter (Yasunami et al., 1991). Both ADH 2 and ADH 3 exhibit polymorphism. The allelic variants, ADH 2 1, ADH 2 2, ADH 2 3, and ADH 3 1, ADH 3 2 code for β1, β2, β3, and γ1, γ2, respectively. These polymorphic genes display different allelic distribution among racial populations (Agarwal and Goedde, 1992; Bosron et al., 1993; Yin, 1994). Based on the kinetic and structural features, human ADH can be grouped into five classes (Vallee and Bazzone, 1983; Jornvall and Hoog, 1995). Class I ADH comprises homo- and heterodimers with α, β or γ subunits. Class II, III, IV enzymes are ππ, χχ, and μμ, respectively. The intraclass and interclass sequence homologies at the amino acid/nucleotide level are approximately 90% and 60%, respectively (Yoshida et al., 1991; Jornvall and Hoog, 1995). Kinetic properties of these five class ADHs vary strikingly (Vallee and Bazzone, 1983; Bosron et al., 1993; Yin, 1994). K m values for ethanol for class I isoenzymes are generally lower than 5 mM, suggesting that they are active after low alcohol consumption. Class II, IV and V enzymes exhibit K m about 30 mM, hence active at moderate to high ethanol concentrations. Class III enzyme does not seem to significantly contribute to ethanol metabolism due to its extremely high K m, > 3 M.

Human stomach class IV alcohol dehydrogenase: molecular genetic analysis.

A partial human stomach alcohol dehydrogenase (ADH) encoding cDNA has been isolated, cloned, and sequenced, which contains 222 nucleotides encoding amino acid residues 227-299 of the ADH subunit. The amino acid sequence deduced from this cDNA was highly homologous with the rat stomach class IV ADH sequence recently reported (81.1% sequence identity). Homology with other human ADH classes was also observed: class I, 58.1% sequence identity; class II, 39.2% sequence identity; class III, 55.4% sequence identity; and class V, 50.0% sequence identity. These results support a proposal that the isolated cDNA encodes a partial sequence for human stomach class IV ADH. This sequence retains val294 for all other human ADH classes reported, as compared with an ala294 at this position reported for rat class IV ADH. This ala residue may contribute to the very high Km values with ethanol for the latter enzyme. In addition, three substitutions are reported for key residues in the coenzyme binding site: 251, gln/ser; 260, gly/asn; and 261, gly/asn, which may contribute to the weak coenzyme binding properties reported for human class IV ADH.

Cloning and expression of a human stomach alcohol dehydrogenase isozyme.

In humans, there is a family of NAD+- and zinc-dependent alcohol dehydrogenases (E.C. 1.1.1.1) that exhibit broad substrate specificity toward aliphatic alcohols (Vallee and Bazzone, 1983, Smith, 1986, and Bosron et al., 1993). The various isozyme subunits are encoded by at least 6 different gene loci (ADH1 through ADH6). Most recently, a new isozyme called σ-ADH or μ-ADH has been isolated from human stomach tissue that has a high K m (about 30 mM) and relatively high catalytic efficiency for ethanol (k c /K m ∼ 52 min-1mM-1)(Wang et al., 1990, Stone et al, 1993, Moreno and Pares, 1991). One or more isozymes with similar electrophoretic mobility are found in the esophagus (Yin et al., 1990).

ETHANOL ELIMINATION IN ALCOHOL-TREATED PREGNANT RATS

The effects of chronic intake of alcohol on ethanol elimination were studied in 20-day pregnant rats, in their foetuses, and in virgin rats. Experimental animals received ethanol in drinking water (from 10% to 25% in 2 months) (alcohol group), whereas controls drank only water. At the end of chronic exposure, alcohol dehydrogenase activity was determined in stomach and liver and cytochrome P-450 was measured in liver. In a complementary assay, the same experimental groups of rats were given an acute dose of ethanol (2 g/kg body wt, 25% w/v) either intragastrically or intraperitoneally, at the end of the chronic exposure, to determine first-pass ethanol metabolism and pharmacokinetic parameters of its elimination. Significant differences were found between alcohol and control groups for liver and stomach alcohol dehydrogenase activity in pregnant rats. Only in virgins did chronic alcohol treatment significantly increase the liver cytochrome P-450 content. In virgin rats, the first-pass metabolism of ethanol was lower in the alcohol group than in control. By contrast, in control rats, the first-pass of ethanol was lower in pregnant, than in virgin, rats. The metabolic rate of ethanol elimination (mg/kg body wt/hr) was clearly enhanced in alcoholic virgin rats, demonstrating that this model of chronic alcoholism induces metabolic tolerance to ethanol. In alcoholic pregnant rats, a surprisingly low theoretical volume of body ethanol distribution (55 ml/100 g body wt vs. 80 ml/100 g body wt in the other groups) masked their metabolic tolerance to ethanol. This preliminary study should be taken into account when evaluating the effects of chronic or/and acute alcohol intake during pregnancy on the circulating ethanol levels in foetuses and on future development of the foetal alcohol syndrome.

Purification and Partial Amino Acid Sequence of a High‐Activity Human Stomach Alcohol Dehydrogenase

To understand the relative importance of alcohol dehydrogenase (ADH) isoenzymes in gastric ethanol metabolism, a stomach-specific ADH (sigma-ADH) was purified to homogeneity from human transplant donor and surgical tissues, and its activity for ethanol oxidation was examined. The enzyme from these tissues had a specific activity at pH 10 of approximately 70 units/mg, about 10 times that reported by Moreno and Parés (J. Biol. Chem. 266:1128-1133, 1991). The enzyme exhibited a high Km for ethanol at pH 7.5 and 10 (29 and 5.2 mM, respectively). This high-activity sigma-ADH isoenzyme migrated on starch and isoelectric focusing gels to a position slightly anodic to the liver pi pi isoenzyme. It was subjected to digestion by endoproteinases, and approximately 40% of the protein was sequenced. The sigma-ADH exhibited 75%, 68%, and 62% sequence identity to the human class I (beta 1), II (pi), and III (chi) isoenzymes, respectively, and 61% identity to the deduced ADH6 amino acid sequence. Phylogenetic analysis indicated that precursors to this high-activity sigma-ADH and the class I isoenzymes diverged more recently than precursors to the class II and III isoenzymes, after reptilian and avian divergence. The high-activity sigma-ADH isoenzyme therefore represents a distinct class of ADH (class IV), more closely related in evolution to the class I isoenzymes than to the other known human isoenzymes.

The Distribution of Ethanol in Postmortem Blood Specimens

Ethanol was determined by gas chromatography in a variety of tissues and body fluids secured at autopsy in 61 cases. The specimens tested included right and left heart blood, femoral blood, pericardial fluid, cerebrospinal fluid, vitreous humor, urine, stomach contents, and brain. Statistical analysis of the cases revealed no significant differences among the various blood sites tested. However, the variations in blood ethanol concentrations among the various sampling sites within each case were as follows: 40 cases showed differences of less than 25%; 16 cases revealed variability between 25% and 50%, 4 cases had differences exceeding 50%. In one case, satisfactory blood analyses could not be accomplished. The larger variances occurred especially in those instances in which stomach alcohol concentration was 0.50% or greater. In one case, the variability amongst the different blood sites exceeded 400% (femoral blood--0.043%, right atrium--0.070%, root of aorta--0.156%); the brain was 0.050%, and the stomach contents was 1.2%. For all 61 cases, variances in blood alcohol content among the different sampling sites in a single cadaver ranged from 1.8 to 428%.

Human stomach alcohol and aldehyde dehydrogenases (ALDH): A genetic model proposed for ALDH III isozymes

Human stomach alcohol and aldehyde dehydrogenases (ALDH): A genetic model proposed for ALDH III isozymes

Human stomach alcohol and aldehyde dehydrogenases (ALDH): a genetic model proposed for ALDH III isozymes.

Isozyme phenotypes of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) from human gastroendoscopic as well as surgical gastric biopsies were determined by starch gel electrophoresis and agarose isoelectric focusing. gamma gamma ADH isozymes were expressed predominantly in the mucosal layer of the stomach, whereas beta beta isozymes were in the muscular layer. In the 56 gastroendoscopic mucosal biopsies examined, the homozygous ADH3 1-1 phenotype was found in 75% of the samples, and the heterozygous ADH3 2-1 phenotype in 25%. Accordingly, the gene frequencies of the alleles ADH1/3 and ADH2/3 were calculated to be 0.88 and 0.12, respectively. Using a modified agarose isoelectric focusing procedure, gastric ALDH I, ALDH II, and up to five ALDH III forms could be clearly resolved. The ALDH III isozymes accounted for more than 80% of the total ALDH activities in gastric mucosa and exhibited Km values in the millimolar range for propionaldehyde at pH 9.0. Forty-five percent of the 55 gastroendoscopic biopsies studied lacked ALDH I isozyme. The complex gastric ALDH III isozyme phenotypes seen in these biopsies fall into three patterns. They can be interpreted by a genetic hypothesis, based on a dimeric molecule, in which there are two separate genes, ALDH3a and ALDH3b, with the ALDH3b locus exhibiting polymorphism. The homozygous phenotypes ALDH3b 1-1 and ALDH3b 2-2 were found to be 4 and 76%, respectively, and the heterozygous ALDH3b 2-1 phenotype 20%, of the total. Therefore, the allele frequencies for ALDH1/3b and ALDH2/3b were calculated to be 0.14 and 0.86, respectively. Several lines of biochemical evidence consistent with this genetic model are discussed.

Genetic Variants of Enzymes of Alcohol and Aldehyde Metabolism

The distribution of genetic variants (or gene markers) for alcohol dehydrogenase, aldehyde dehydrogenase, aldehyde oxidase, and aldehyde reductase isozymes has been examined among 12 inbred strains of mice. Electrophoretic variants are described for the major liver and stomach alcohol dehydrogenase isozymes (ADH-A2 and C2); liver, kidney, and stomach aldehyde dehydrogenase isozymes (AHD-1; AHD-2; AHD-4); a liver-specific aldehyde reductase (AHR-A2); and a liver aldehyde oxidase isozyme (AOX-2). Genetically determined activity variants were observed for a testis-specific aldehyde dehydrogenase (AHD-6); liver and kidney aldehyde reductase isozymes (AHR-3 and AHR-4); and the major liver AOX isozyme (AOX-1). These variants may serve as useful gene markers in alcohol research involving animal model studies with inbred strains in mice.

The Comparison of Alcohol Concentrations in Postmortem Fluids and Tissues

Fluid-tissue/blood alcohol ratios were calculated for a number of cases. The use of such factors to determine the blood alcohol concentration (BAC) becomes important when a blood specimen is not available or is contaminated. It was shown that estimates of blood alcohol concentrations derived from other physiological fluids or tissues can only be expressed as lying within a wide concentration range. Estimations of the BAC can be improved by using the stomach alcohol concentrations to determine if the decreased was in an absorption or postabsorption phase at the time of death.

Human Stomach Alcohol Dehydrogenase: Isoenzyme Composition and Catalytic Properties

Two isoenzymes of alcohol dehydrogenase have been purified from human stomach and characterized with regard to electrophoretic mobility and kinetic properties with ethanol, hexanol, and acetaldehyde. Both undergo a time-dependent formation of multiple electrophoretic bands; the total amount of alcohol dehydrogenase activity in an average human stomach is only about 0.2% of that of the liver.

The genetics of alpha-hydroxyacid oxidase and alcohol dehydrogenase in the mouse: evidence for multiple gene loci and linkage between Hao-2 and Adh-3.

Electrophoretic polymorphisms for stomach alcohol dehydrogenase (ADH-C2) and kidney L-alpha-hydroxyacid oxidase (HAOX-B4) have been identified in an Asian subspecies of mouse, Musmusculus castaneous. These variants are inherited in a normal Mendelian fashion with two alleles in each case showing codominant expression. The structural gene loci for those enzymes (Adh-3 and Hao-2, respectively) are apparently linked (17.6% recombinants) in this organism, whereas the multiple gene loci for HAOX, Hao-1 (encoding the A4 liver isozyme) and Hao-2, exhibited independent segregation and are unlinked (50% recombinants). Evidence is presented for 3 ADH loci: ADH-1, encoding liver ADH-A2 which exhibits high activity with ethanol (SELANDER, HUNT and YANG 1969; ADH-2, liver and stomach ADH-B2 using 2-hexene-1-ol as substrate; and Adh-3, stomach ADH-C2 using both benzyl alcohol and 2-hexene-1-ol as substrate.

Characterization of a nonhepatic alcohol dehydrogenase from rat hepatocellular carcinoma and stomach

Ethanol oxidation by the soluble fraction of a rat hepatoma was compared to that of the liver. Ethanol oxidation by the hepatoma was NAD +-dependent and sensitive to pyrazole, suggesting the presence of alcohol dehydrogenase. At low concentrations of ethanol (10.8 m m) the alcohol dehydrogenase activities of hepatoma and liver supernatant fractions were comparable. When the concentration of ethanol was raised to 108 m m, the activity of the liver enzyme decreased, whereas the activity in hepatoma supernatant fractions was strikingly elevated. m-Nitrobenzaldehyde-reducing activity was also conspicuously higher in hepatoma supernatant fractions. By contrast the ability to metabolize steroids and cyclohexanone was less than that in supernatant fractions of the liver. Electrophoresis of the liver supernatant fractions on ionagar at pH 7.0 revealed only one component that oxidized ethanol. On the other hand, hepatoma supernatant fractions contained two components with alcohol dehydrogenase activity; one with the same electrophoretic mobility as the liver enzyme, the other showing a slower rate of migration. The latter component, which is absent in the liver, is referred to as hepatoma alcohol dehydrogenase. By electrophoresis on starch gels at pH 8.5, it could be demonstrated that the liver and hepatoma enzymes moved in opposite directions. The liver and hepatoma enzymes differ in electrophoretic mobility, susceptibility to heat treatment, pH activity optimum and some catalytic properties. The substrate specificity of the hepatoma enzyme is narrower than that of liver alcohol dehydrogenase; cyclohexanone or 3β-hydroxysteroids of A/B cis configuration and the corresponding 3-ketones are not substrates for the hepatoma enzyme. The overall substrate specificity characteristics are, however, similar to those of the liver enzyme in that the effectiveness of substrates increases with an increase in chain length and introduction of unsaturation or an aromatic group. Both liver and hepatoma alcohol dehydrogenase cross-react with antibody to horse liver alcohol dehydrogenase EE. The Michaelis constant for ethanol with the hepatoma enzyme is 223 m m, compared to 0.3 m m for liver alcohol dehydrogenase; at 1.0 m ethanol the hepatoma enzyme is not fully saturated with substrate. The Michaelis constant for 2-hexene-1-ol is 0.3 m m, indicating that the hepatoma enzyme is better suited for dehydrogenation of longer chain alcohols. Stomach alcohol dehydrogenase has kinetic properties comparable to those of the hepatoma enzyme, as well as similar electrophoretic mobility. The hepatoma enzyme can be detected in the serum of rats bearing hepatomas.