The nitroreduction of chloramphenicol by human liver tissue.

Fresh-frozen human liver tissue was assayed for its ability to reduce the nitrogroup of R--NO2 to the amine. All 10 livers examined exhibited demonstrable reductase activity. The reduction was potentiated by NADPH and abolished by boiling the liver homogenates. The nitroreductase activity varied among the different livers by as much as severalfold. These findings show that ability of the human liver to reduce R--NO2 and support the hypothesis that certain toxic intermediates of the nitroreduction of R--NO2 may be responsible for the aplastic anemia associated with this drug.