Ethanol consumption and hepatic enzyme activity

Effect of water-soluble propolis administration on the ethanol-induced hangover in rats

Water soluble propolis was prepared using β-cyclodextrin, and its effect on an ethanol-induced hangover was examined in Sprague-Dawley (SD) rats fed with ethanol. When SD rats were administrated with propolis 30 min after ethanol feeding, ethanol content in the rat serum decreased 2.1 times 1 h after ethanol feeding. Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activity in rat liver increased 3.0 and 4.4 times, respectively, 1 h after ethanol feeding and administration of propolis 30 min after ethanol feeding. There were no differences in the expression of ADH and ALDH genes regardless of propolis administration. These results indicated that a decrease in ethanol content in the serum was not due to an increase in the expression of ADH or ALDH genes but rather, an increase in activities of ADH and ALDH.

Gene markers for alcohol-metabolizing enzymes among recombinant inbred strains of mice with differential behavioural responses towards alcohol

The genetic variability of alcohol dehydrogenase (C2 isozyme), aldehyde dehydrogenase (A2 isozyme) and aldehyde oxidase (A2 isozyme) has been examined among recombinant inbred strains of mice which have been previously studied concerning their differential behavioural responses towards alcohol. The results showed no correlation between biochemical phenotype for these loci and behavioural response.

Diminished alcohol preference in transgenic mice lacking aldehyde dehydrogenase activity

Aldehyde dehydrogenase (ALDH) 2 plays a major role in the detoxification of aldehyde and is known to be responsible for alcohol preference. A diminished enzyme activity due to mutation of the Aldh2 gene is associated with high alcohol sensitivity and a low alcohol tolerance in humans. The genomic background distinguishing an alcohol preference and avoidance in various inbred mouse strains is not clear. We created Aldh2-negative mice by transgenic knockout of the Aldh2 gene into the high alcohol preference C57BL/6 background. The Aldh2 gene targeting (Aldh-/-) mice exhibited an alcohol avoidance characteristic. After free-choice ethanol and water drinking, brain and liver acetaldehyde concentrations of Aldh2-/- mice were almost equal to those of wild-type (Aldh2+/+) mice although the Aldh2-/- mice drank less ethanol than the Aldh2+/+ mice. This result indicates that a direct effect of the Aldh2 genotype plays an important role on alcohol preference and acetaldehyde concentration in the brain is correlated with alcohol avoidance. This highlights the potential benefits of alcoholism and alcohol-related disease research in the animal model of ALDH2 alleles.

Behavioral effects and pharmacokinetics of propofol in rats selected for differential ethanol sensitivity

High- and low-alcohol sensitivity (HAS and LAS) rats have been selected for their differences in ethanol-induced sleep time. The rats also differ in sensitivity to pentobarbital, halothane, isoflurane, and enflurane. To determine if this sensitivity extended to propofol, the anesthetic requirements were measured. In this study, the sleep time and the tissue levels of propofol at awakening, as well as the pharmacokinetics, were evaluated. Propofol was administered intravenously. For one group of rats, sleep times were measured; blood and brain samples were taken at awakening. Blood samples were collected in another group of rats at frequent intervals from 0 to 90 min after injection. Propofol concentration of the samples was determined by gas chromatography. The pharmacokinetic analysis was performed using a nonlinear least-squares regression program. Sleep time was not different; however, blood and brain propofol levels at awakening showed a small, but significant difference between HAS and LAS rats. Propofol blood concentration-time curve data were fitted to a three-compartment model. Pharmacokinetic parameters were also not different between the rat lines. However, sleep time was 50% longer in female rats than male rats in both strains (p < 0.0001). The rates of propofol clearance were slower in female rats, because of different rates of disappearance from the second compartment. The observations suggest that the genetic selection for ethanol sensitivity selection for propofol sensitivity was not nearly as intense and presumably involves some different genes. These two central nervous system depressants would seem to differ significantly in their mechanism of action.(ABSTRACT TRUNCATED AT 250 WORDS)

Liver cytosolic aldehyde dehydrogenases from "alcohol-drinking" and "alcohol-avoiding" mouse strains: purification and molecular properties

Liver cytosolic aldehyde dehydrogenases (AHD-2) have been isolated in a highly purified state from "alcohol-drinking" (C57BL/6J) and "alcohol-avoiding" (DBA/2J) strains of mice. The purified enzymes were resolved into three major and one minor form of activity by isoelectric focusing (IEF) techniques and showed similar zymogram patterns. The enzymes had identical subunit sizes on SDS-polyacrylamide gels: 53,000. Gel exclusion chromatography, using Ultrogel AcA34, indicated that the enzymes were dimers. The enzymes exhibited biphasic kinetic characteristics and were readily distinguished from each other. The purified forms of AHD-2 from C57BL/6J and DBA/2J mice exhibited two apparent Km values in each case: 10 microM/100 microM and 30 microM/330 microM respectively. AHD-2 exhibited a broad pH optimum in the range 7.0-9.0 and was very sensitive towards disulphuram inhibition, with 50% inhibition occurring at 0.17 microM. The kinetic results support proposals that AHD-2 may be the primary enzyme for oxidizing acetaldehyde during ethanol oxidation in vivo.

Mouse mitochondrial aldehyde dehydrogenase isozymes: purification and molecular properties

Aldehyde dehydrogenase isozymes (AHD-1 and AHD-5) have been isolated in a highly purified state from extracts of mouse liver mitochondria. The enzymes have distinct subunit sizes, as determined by SDS/polyacrylamide gel electrophoresis: AHD-1, 63,000; AHD-5, 49,000. Gel exclusion chromatography, using sephadex G-200, indicated that both isozymes are dimers, although AHD-1 may also exist as a monomeric form as well. The enzymes exhibited widely divergent kinetic characteristics. The purified allelic forms of AHD-1, AHD-1A (C57BL/6J mice) and AHD-1B (CBA/H mice), exhibited high Km values with acetaldehyde as substrate, 1.4 mM and 0.78 mM respectively, whereas AHD-5 exhibited a low Km value with acetaldehyde of 0.2 microM. In addition, the isozymes exhibited distinct pH optima for catalysis (AHD-1, pH range 6.5-7.5; AHD-5, pH range 8.5-10.0), and were differentially sensitive towards disulphuram inhibition, with 50% inhibition occurring 13 and 0.1 microM for the AHD-1 and AHD-5 isozyme respectively. Based upon the kinetic characteristics, it is suggested that AHD-5 may be the primary enzyme for oxidizing mitochondrial acetaldehyde during ethanol oxidation in vivo.

Biochemical and genetic studies on mouse aldehyde dehydrogenases

Aldehyde dehydrogenase (AHD) exists as isozymes which are differentially distributed among tissues and subcellular fractions of mouse tissues. Genetic variants for liver mitochondrial (AHD-1) and cytoplasmic (AHD-2) isozymes have been used to map the responsible loci (Ahd-1 and Ahd-2) on chromosomes 4 and 19 respectively. Evidence for a regulatory locus (Ahd-3r) controlling the inducibility of the mouse liver microsomal isozyme (AHD-3) has also been obtained. More recent studies have described genetic and biochemical evidence for three additional AHD isozymes: a stomach isozyme (AHD-4); another liver mitochondrial enzyme (AHD-5); and a testis isozyme (AHD-6). Genetic analyses have indicated that AHD-4 and AHD-6 are encoded by distinct but closely linked loci on the mouse genome (Ahd-4 and Ahd-6), which segregate independently of Ahd-1 and Ahd-2. Liver mitochondrial isozymes, AHD-1 and AHD-5, have been purified to homogeneity using affinity chromatography. The very high affinity of AHD-5 for acetaldehyde suggests that this enzyme is predominantly responsible for acetaldehyde oxidation in mouse liver mitochondria.

Stimulant and depressant properties of sedative-hypnotics in mice selectively bred for differential sensitivity to ethanol

A genetic analysis of sedative-hypnotic response in selectively bred Long-Sleep (LS) and Short-Sleep (SS) mice showed LS mice to be more depressed by acetaldehyde, ethanol (ETOH), and t-butanol, but less sensitive to pentobarbital. Intermediate inheritance was shown by the two reciprocal F1 hybrids for the alcohols, but dominance to the LS genotype occurred for the aldehyde and the barbiturate. At several subhypnotic doses of ETOH in two experiments, LS mice showed less locomotor stimulation and greater disruption of coordination than the SS mice. The two reciprocal F1 hybrids did not differ from one another and had dose-response curves intermediate to the two parental lines. Study of the effects of t-butanol on locomotor activity revealed a pattern of line differences similar to that for ETOH. The genetic selection for LS and SS mice appears to have differentiated loci that pleiotropically influence a variety of behavioral responses to alcohols.