Genetic and environmental factors affecting ethanol metabolism in man.

Abstract

The relative contribution of genetic and environmental factors to maintaining twofold differences in rates of ethanol elimination from plasma was examined in 14 sets of nonmedicated, nonhospitalized healthy twins. After a single oral dose of 1 ml. per kilogram of 95 per cent ethanol, intrapair differences in rates of elimination were less in identical than in fraternal twins. Thew results indicate that individual differences in rates of ethanol elimination among the 28 twins were genetically controlled and that environmental factors played a negligible role. In 6 prisoners in solitary confinement, rates of ethanol metabolism increased in 3 but declined in the remaining 3 after 21 days of ethanol administration. Rates of antipyrine elimination from plasma were accelerated by ethanol administration in each of the 6 volunteers. Considerable individual variation occurred in the degree to which ethanol shortened plasma antipyrine half‐lifes; reduction ranged from 4 to 37 per cent of the initial antipyrine half‐life. These results suggest that ethanol administration for 21 days at this dosage fails to alter consistently the rate of its own metabolism but increases antipyrine metabolism in all subjects to varying extents.