Our previous finding of a glutathione (GSH) deficiency in aging or senescent mice suggested that a concomitant decrease in detoxification capacity also may occur. To test this, mice at different biological stages of the life span (growth, maturity, aging or senescence) were injected with various doses of acetaminophen (APAP), and GSH depletion and recovery rates were determined. At intervals for 24 hr, samples of blood and other tissues were obtained, processed, and analyzed for reduced GSH, glutathione disulfide (GSSG), cysteine, and cystine using HPLC with dual electrochemical detection. In the uninjected controls, the GSH concentration decreased about 30% in all tissues of the aging mouse, but the GSSG cysteine, and cystine levels were unchanged during the life span. APAP administration depleted liver and lung GSH contents in a dose- and time-dependent manner. Four hr after APAP administration, hepatic GSH levels of all ages had decreased 70-80%. After 24 hr, the GSH levels of the young, growing (3-6 months), and mature (12 months) mice recovered to 94 and 66%, respectively, of the controls. In contrast, the level in aging (31 months) mice rose only 41%, a lower recovery that was correlated with their decreased GSH content. The lungs of old mice also were GSH-deficient but differed from liver, for there was less GSH depletion by APAP and no decrease in GSH recovery. Thus, these findings demonstrate clearly the occurrence of decreased detoxification capacity in the GSH-deficient, aging mouse.