HUMAN GASTRIC ALCOHOL-DEHYDROGENASE ACTIVITY - EFFECT OF AGE, SEX, AND ALCOHOLISM

As various isoenzymes of gastric alcohol dehydrogenase exist and as th e effect of sex and age on these enzymes is unknown, this study measur ed the activity of gastric alcohol dehydrogenase at high and low ethan ol concentrations in endoscopic biopsy specimens from a total of 290 p atients of various ages and from 10 patients with chronic alcoholism. Gastric alcohol dehydrogenase was also detected by immunohistological tests in biopsy specimens from 40 patients by the use of a polyclonal rabbit antibody against class I alcohol dehydrogenase. A significant c orrelation was found between the immunohistological reaction assessed by the intensity of the colour reaction in the biopsy specimen and the activity of alcohol dehydrogenase measured at 580 mM ethanol. While a lcohol dehydrogenase activity measured at 16 mM ethanol was not signif icantly affected by age and sex, both factors influenced alcohol dehyd rogenase activity measured at 580 mM ethanol. Young women below 50 yea rs of age had significantly lower alcohol dehydrogenase activities in the gastric corpus and antrum when compared with age matched controls (SEM) (6.4 (0.7) v 8.8 (0.6) nmol/min/mg protein; p<0.001 and 6.0 (1.3 ) v 9.5 (1.3) nmol/min/mg protein; p<0.001). Over 50 years of age this sex difference was no longer detectable, as high Km gastric alcohol d ehydrogenase activity decreases with age only in men and not in women. In addition, extremely low alcohol dehydrogenase activities have been found in gastric biopsy specimens from young male alcoholics (2.2 (0. 5) nmol/min/mg protein), which returned to normal after two to three w eeks of abstinence. The activity of alcohol dehydrogenase in the human stomach measured at 580 mM ethanol is decreased in young women, in el derly men, and in the subject with alcoholism. This decrease in alcoho l dehydrogenase activity may contribute to the reduced first pass meta bolism of ethanol associated with raised ethanol blood concentrations seen in these people.