Induction of intracellular glutathione in alveolar type II pneumocytes following BCNU exposure.

N,N'-bis(2-chloroethyl)-N-nitro-sourea (BCNU) is a potent inhibitor of glutathione reductase (GSSG-Red) activity in both tissues and cells. We examined the effects of treating alveolar type II cells with BCNU and found that a marked decrease in cellular GSSG-Red activity occurred in these cells associated with a time-dependent increase in cellular glutathione (GSH) concentrations. The increase in GSH was not found to be related to changes in cellular gamma-glutamyl transpeptidase activity, gamma-glutamylcysteine synthetase activity, nor increased intracellular transport of cystine. When the BCNU-exposed cells were incubated with hydrogen peroxide to produce oxidant stress, the cells exhibited increased susceptibility to oxidant damage when compared with controls, despite the fact that cellular concentrations of GSH were markedly elevated.