The deficiency of adenosine deaminase (ADA), the enzyme that catalyzes the hydrolytic deamination of adenosine and deoxyadenosine (dAdo)is associated with severe immune deficiency and abnormalities in the functioning of many organs including the nervous system. The molecular link between the metabolic disorder and the neurological manifestations is unknown. In order to investigate the mechanisms underlying the neurological manifestations associated with ADA deficiency, human astrocytoma ADF cells have been treated with the ADA inhibitor deoxycoformycin (dcF) and dAdo, which accumulates in the absence of ADA. Levels of lactate and purine metabolites released into the culture medium have been determined by spectrophotometric and HPLC methods, respectively. After 15 hours of treatment, it was observed a significant decrease of lactate, decrease in viability (measured either as increased activity of lactate dehydrogenase in culture medium or as MTT reduction capacity in adherent cells), increase of caspase-3 activity, and increase of mitochondrial reactive oxygen species (detected by using MitoTracker Red CM-H₂XROS and confocal microscopy). Treatment of cells with antioxidants did not restore viability. These results suggest that the decrease in lactate production by glial cells could lead to reduced supply of lactate to neurons and might contribute to psychomotor deficits seen in patients with ADA deficiency