Glutathione biosynthesis from sulfur-containing amino acids in enriched populations of Clara and type II cells and macrophages freshly isolated from rabbit lung.

The glutathione content of freshly isolated rabbit alveolar type II cells, Clara cells and macrophages was depleted by incubating with diethyl maleate and the ability of these cell types to resynthesize glutathione from the sulfur-containing amino acids, cysteine, cystine and methionine was determined. Cysteine and methionine were taken up at a similar rate into each of the cell types, with cystine uptake occurring at a 10- to 14-fold lower rate. The cells were best able to utilize cysteine for glutathione resynthesis and the rates of both uptake and synthesis were fastest in macrophages and slowest in type II cells. There was no evidence for participation of a cystathionine pathway for glutathione synthesis in any of the cell types.