GSH and GSH transport under fasting conditions. After three hours, the inputs of cysteine, methionine, glycine, glutamate, and serine are reduced to 1/3 of normal. The intracellular GSH + GSSG concentration declines slowly over the 48 hour period to about 50% of normal and the rate of GSH export declines to 67% of normal consistent with the experiments reported in . The cytosolic and blood cysteine concentrations decline proportionally to GSH. The methionine cycle metabolites and fluxes equilibrate rapidly.