Cyclic expression of class I alcohol dehydrogenase in male rats treated with ethanol

Continuous infusion of ethanol-containing diets has been demonstrated to ge nerate well-defined pulses in blood and urine ethanol concentrations that o ccur with a frequency of approximately 6 days. The present study aimed to d etermine if hepatic class I alcohol dehydrogenase was the cause of these cy cles. Adult male rats were fed an ethanol-containing diet by continuous int ragastric infusion. Hepatic ADH activity, class I ADH mRNA level and rate o f class I ADH gene transcription fluctuated in a cyclic pattern that positi vely correlated with UECs, and inhibition of ADH with 4-methylpyrazole abol ished the UEC pulses. These data demonstrate for the first time an ethanol- dependent regulation of rat hepatic class I ADH. The cyclic behavior of the ethanol levels correlates with changes in class I ADH expression and impli es adaptability of the ethanol eliminating system to high concentrations of alcohol. (C) 2000 Academic Press.