The glutamine (Gln) has been termed ‘conditionally essential’ because is often depleted during times of catabolic stress like cancer, severe infection (sepsis) and burn injury. This characteristic depletion is attributed to its role as a metabolic intermediate aporting carbon and nitrogen for the synthesis of other amino acids, fatty acids, nucleic acids and proteins and also supplying a source of fuel for dividing cells. Gln is an essential component of glutathione (GSH) homeostasis. GSH is the primary intracellular antioxidant, scavenger of free radicals, peroxides and other reactive species. As a consequence of their exhaustion the process of apoptosis is triggered. Gln deprivation ultimately elicits apoptosis by intrinsic and/or extrinsic pathways, depending on the cell type (1). The aim of these work was to assess the glutamine and serum deprivation effects on the cell cycle and GSH compartimentation. Cells was cultured in DMEM media supplemented with 10% fetal calf serum (FCS) using 2×10⁵ cells cm², and grown at 37°C in a humidified atmosphere of 5% CO₂ air mixture for 24 h. To induced apoptosis cultured medium was removed and the cells were cultured in Gln, serum and Gln-serum deprived medium for 48 h. In control cells medium was changed too. Cells were treated with propidium iodide (IP), to identify dead cells, and annexine V, for apoptosis measurement, then the of apoptosis and cells cycle were determined by flow cytometry. The GSH levels were determined by spectrophotometry. To visualize GSH localization, cells were observed with a Leica confocal microscope. Triple staining was applied: propidium iodide (Hoechst; 2 mg/ml) to localize nucleus and CellTracker green 5-chloromethylfluorescein diacetate (5mM; CMFDA), which marks GSH (specificity 95%). Our results show that the cell death and apoptosis levels are higher in the conditions of Gln deprivation, than in serum-deprived cells and control (33.6±3.41; 23±1.9 and 7.45±1.6, p<0.05, respectively). Also GSH levels in these cells were significantly lower compared with control cells and serum-deprived cells (73±28, 95±29.3 and 46±12.6 nmol/mg prot, p<0.05, respectively). By confocal microscopy we observed that serum deprivation caused nuclear GSH compartimentation, while in Gln-deprived cells the GSH distribution was homogeneous. Our results suggest that those cells with higher nuclear GSH levels are more resistant to apoptosis.