Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.1.1.1 (alcohol dehydrogenase)
 9,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ethanol metabolism to acetaldehyde by NAD+-dependent alcohol dehydrogenase (ADH) activity reduces, in part, androgen secretion by rat Leydig cells. ADH in Leydig cells is proposed to decrease the NAD+/NADH ratio and thereby inhibit NAD+-dependent delta 5-3 beta hydroxysteroid dehydrogenase-isomerase activity and increase NADH-dependent 5 alpha-androstane-3 beta-hydroxysteroid dehydrogenase activity. Although the reciprocal changes in these steroidogenic enzyme activities by ethanol are attributed to ADH activity, there is very little information about this enzyme in purified Leydig cells. The present studies examined specific characteristics of this enzyme in metrizamide-gradient purified Leydig cells. ADH activity was linear with respect to protein concentration and incubation time. The activity was concentrated in the soluble fraction, and the most effective cofactor was NAD+. The apparent Km for ethanol was 0.50 mM, and the Vmax was 53 nmol NADH/10 min/mg protein. When Leydig cell cytosol was incubated with a fixed ethanol concentration (50 mM) and increasing NAD+ and the data were plotted according to Lineweaver-Burk, a biphasic curve was observed with apparent Km's of 0.032 and 0.17 mM. The optimum pH for the enzyme was 8.2, and the enzyme was inhibited in a dose-dependent manner by 4-methylpyrazole. These studies further characterize ADH activity in purified Leydig cells and demonstrate that this enzyme exhibits many characteristics similar to the more widely studied liver enzyme(s).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Partial characterization of alcohol dehydrogenase activity in purified rat Leydig cells. 378 76

These studies provide evidence for the presence of a microsomal ethanol oxidizing system in rat Leydig cells. Activity of the microsomal ethanol oxidizing system in Leydig cells was 47.4 +/- 4.1 nmol acetaldehyde per 20 min per mg protein, while activity in crude interstitial cells was 26.0 +/- 5.4 nmol. This suggests that among cells comprising interstitial cells, activity is concentrated in Leydig cells. Activity was linear with respect to protein concentration and incubation time. The highest specific activity was observed in the microsomal fraction. The most effective cofactor was NADPH. The apparent Km for ethanol was 4 mM, suggesting that this system could effectively metabolize ethanol at concentrations found in the blood of males who drink. The apparent Km for NADPH was 11 microM. The activity in Leydig cells was unaffected by 4-methylpyrazole or potassium cyanide, which inhibit alcohol dehydrogenase and catalase activities, respectively. These data provide strong evidence for an enzyme system in Leydig cell microsomes which is capable of metabolizing ethanol.
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PMID:Microsomal ethanol-oxidizing system in purified rat Leydig cells. 382 73

The direct effect of ethanol on dihydrotestosterone (DHT) conversion to 5 alpha-androstan-3 beta,17 beta-diol (3 beta-diol) and 5 alpha-androstan-3 alpha,17 beta-diol (3 alpha-diol) by adult rat Leydig cells was examined. Concentrations of ethanol comparable to blood levels of alcoholic men (2.2 - 65 mM) increased DHT conversion to 3 beta - and 3 alpha-diol, in direct relation to the dose of ethanol added; a 2-fold or greater stimulation was observed. Because this effect was blocked by 4-methylpyrazole or a saturating NADH concentration, these results suggest that this action is mediated by Leydig cell alcohol dehydrogenase activity. These results may have significant impact in the testis and/or other DHT sensitive tissues because ethanol may decrease the availability of the proposed active androgen.
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PMID:Ethanol directly increases dihydrotestosterone conversion to 5 alpha-androstan-3 beta,17 beta-diol and 5 alpha-androstan-3 alpha,17 beta-diol in rat Leydig cells. 637 73