Ethanol Metabolism by Rat Precision-Cut Liver Slices. PCLS were cultured at 24, 48, 72 and 96 hours in the presence of 25 mM ethanol (Ethanol), and in the presence of both 25 mM ethanol and 0.50 mM 4-MP (Ethanol + 4-MP). Since Control PCLS do not metabolize ethanol, the data for Control and Control +4-MP are not shown. Media were changed every 24 hours and assessed for ethanol concentrations (μmole/mg) by headspace gas chromatography. Data are expressed as the mean ± S.E.M. μmoles of ethanol metabolized/24 hours/mg of PCLS protein of five separate experiments. The addition of 4-MP significantly inhibited ethanol metabolism at all times, *P < 0.01.