Ethanol sulfation by the pulmonary ethanol metabolizing system (PET).

Rat lung slices incubated in a Krebs Ringer bicarbonate buffer metabolized ethanol by sulfocunjugation at a rate of about 500 mumoles/g x hr when the ethanol concentration was 11 mM. Tissue slices from dog and rabbit lung also were able to metabolize this alcohol showing similar time curves and rates. In all cases ethanol metabolism showed a dependence on the concentration of ethanol which is typical of allosteric enzymes. The calculated Hill coefficient was between 1.69 and 2.07 in the three species studied. Sulfoconjugation of ethanol by rat lung slices showed a Km for ethanol of 26.59 mM and a Vmax of 11,357 mumoles/g x hr. The Km for ethanol determined with dog lung slices was 20.93 mM and Vmax was 8,052 mumoles/g x hr. In the case of rabbit lung, Km for ethanol was 20.15 mM whereas Vmax was 17,379 mumoles/g x hr. Preliminary evidence would seem to indicate that the human lung is also able to metabolize ethanol by conjugation with sulfate. These results suggest that the lung is endowed with a remarkable potential to metabolize ethanol by sulfoconjugation. In vivo, however, sulfoconjugation may be limited by substrate availability.