Alcohol and aldehyde dehydrogenase activity in the stomach and small intestine of rats poisoned with methanol

The activities of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (A LDH) were measured with fluorogenic naphthaldehydes in the stomach and smal l intestine homogenates of rats dosed with 6 g methanol/kg bw after 6, 12, 24 h and 2, 5, 7 days. After intoxication with a sublethal dose, the ADH ac tivity measured with these naphthaldehydes and ALDH activities in the stoma ch and small intestine were significantly decreased. This inhibition is str onger in the stomach and probably depends on cell damage and protein denatu ration. We conclude that the activity measured with 6-methoxy-2- naphthalde hyde (MONAL-62) may be due to the activity of rat ADH-1 isoenzyme, and the activity detected with 4-methoxy-1-naphthaldehyde (MONAL-11) to the activit y of rat ADH-2 isoenzyme.