Variations in alcohol metabolism: influence of sex and age.

Alcohol-induced sleep time was measured subsequent to the intraperitoneal injection of a 3.5 g x kg-1 dose. The old male group had a sleep time approximately 4 times that of the young male group and approximately twice that of the old female group. Blood alcohol concentrations at time of awakening were nearly identical in all groups, indicating the difference in sleep time is not due to an altered CNS sensitivity. Measurement of in vivo alcohol disappearance rate indicates the old male group is different from the other groups because of a slower rate of alcohol metabolism. Although changes in hepatic alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activities were seen, the changes do not explain the observed decrease in alcohol metabolism observed in the old male group. These data provide further evidence that hepatic ADH and ALDH activities are not rate limiting in alcohol metabolism.