Participation of thiamin in hepatic microsomal ethanol oxidizing system

In order to assess the role of thiamin on ethanol metabolism, changes in the activity of hepatic microsomal ethanol oxidizing system (MEOS) were measured in rats fed thiamin deficient diet for 4-6 weeks. In thiamin deficient rats, the activity of hepatic MEOS was significantly decreased as compared with control rats. In vitro addition of thiamin or thiamin pyrophosphate (TPP) caused the restoration of the decreased MEOS activity, and this effect was dependent on the concentration of thiamin in rat liver microsomal fraction. Thus, thiamin partly involves in the oxidation of ethanol, and chronic thiamin deficiency predisposes to impair the ethanol oxidation, and consequently to increase the toxicity due to ethanol.