Alcohol dehydrogenase (ADH) has been analysed in 36 endoscopic biopsies of normal gastric body and/or antrum mucosa, from 31 individuals with an age between 17 and 79 years. Oesophageal, duodenal and oral mucosa specimens have been also examined. Stomach mucosa contains three isozyme types: the γγ-ADH forms (class I), σσ-ADH forms (class IV) and χχ-ADH (class ifi). γγ-ADH was present in all gastric samples, while σσ-ADH was detected in all body specimens (n = 15) but only in eight of 20 antrum biopsies. The presence of high σσ-ADH activity in oral and oesophageal mucosa confirms the distribution of class IV in the upper gastrointestinal tract where it may serve as a first metabolic barrier against ingested alcohols and aldehydes. Considering all gastric specimens, ADH activity was 5.78 ± 2.61 mU/mg of protein with 100 mM ethanol, pH 10.0. ADH activity was higher in men than women and in gastric body than in antrum, although differences did not reach statistical significance. However, activity was significantly higher in subjects below 50 years than those older than 50 years. Furthermore, an inverse correlation was found between gastric ADH activity and age (r = -0.40, P < 0.02). In old subjects ADH activity was significantly higher in gastric body (5.87 ± 1.22 mU/mg) than in antrum (4.14 ± 1.78 mU/mg) (P = 0.03). Differences in activity between samples from each ADH3 phenotype were statistically not significant but corresponded to those expected from the kinetic constants of the respective γγ-ADH isozymes, which suggests that ADH polymorphism affects activity. conclude that age has a major effect on gastric ADH, while stomach region and ADH phenotype also influence its activity. © 1994 Medical Council on Alcholism.
|Journal||Alcohol and Alcoholism|
|Publication status||Published - 1 Nov 1994|