Concentration dependency of ethanol elimination rates in baboons: effect of chronic alcohol consumption

Ethanol elimination rates were measured in 7 baboons fed alcohol for 2--7 yr (and their controls) by using a constant ethanol infusion to maintain blood ethanol at three different levels; 5, 10, and 50 mM. Ethanol elimination rates were significantly faster at a blood ethanol level of 50 mM than at 10 or 5 mM in both alcohol-fed and control animals. The difference between 50 mM and 5 mM concentration was 36% in alcohol-fed and 25% in control animals. In baboons fed ethanol chronically, the ethanol elimination rates were significantly faster than in pair-fed controls at 50 mM (179 +/- 10.0 mg/kg/hr versus 144 +/- 9.8) and at 10 mM (148 +/- 4.1 versus 114 +/- 8.2), but not at 5 mM. Even if one takes into account the extrahepatic losses, these differences cannot be explained solely by the elimination of ethanol through the low Km alcohol dehydrogenase pathway, and these observations indicate that a non-ADH system significantly contributes to ethanol elimination in vivo, especially in alcohol-fed baboons.