Alcohol and aldehyde dehydrogenase activity measured with fluorogenic substrates in the liver of rats poisoned with methanol.

The effect of methanol poisoning of rats on the hepatic activities of enzymes metabolizing alcohols was evaluated. The activities of alcohol (ADH) and aldehyde dehydrogenase (ALDH) in the liver of rats dosed with 1.5 and 3 g of methanol/kg b.w. were measured with new fluorogenic substrates (4-methoxy-1-naphthaldehyde [MONAL-41] for ADH and 6-methoxy-2-naphthaldehyde [MONAL-62] for ADH and ALDH) after 6, 12 and 24 hours and 2, 5 and 7 days. The methanol intoxication led to a dose dependent induction of ADH and ALDH activities. The higher dose of methanol induced the activities measured with both MONAL-41 and MONAL-62 with the peak on day 5; its effect was largest on the activity of ADH measured with MONAL-41. Only ADH activity measured with this substrate was induced by the lower dose of methanol during the whole time of the experiment; the activity of ADH measured with MONAL-62 and that of ALDH were induced only on day 1 of the intoxication. It is evident that sublethal methanol intoxication induces the hepatic activities of ADH and ALDH measured with fluorogenic substrates, and this induction depends on the dose of this alcohol.