INTRODUCTION: Simultaneous pancreas-kidney transplantation became the first treatment option for type I diabetes patients with end stage renal failure. However, graft acute pancreatitis remains a frequent complication (35%) on immediate pos-operative period and it may contribute to graft loss. Ischemia-reperfusion injury may be involved in the pathogenesis of graft acute pancreatitis. Gene expression is strongly modified after cellular injury. Glutathione-S-transferases (GST) enzymes provide protection against electrophiles and products of oxidative stress, by catalyzing the formation of glutathione conjugates and by eliminating peroxides during ischemia-reperfusion injury. N-acetyl cysteine (NAC) has been shown to improve pancreatic microcirculation alterations in experimental pancreas transplantation. AIM: Evaluate pancreatic injury and expression level of isoform GST-α after pancreatic ischemia-reperfusion induction on rat model. METHODS: Twenty-four Wistar rats weighting 300-350g were divided into four groups: Group 1 - sham; Group 2 - ischemia-reperfusion; Group 3 - ischemia-reperfusion plus NAC iv; Group 4 - ischemia-reperfusion plus NAC po. Splenic pancreatic portion underwent to 1 hour ischemia followed by 4 hours of reperfusion. Group 3 received intravenously150mg/kg body weight 15 minutes before reperfusion followed by 50mg/kg body weight during the remaining time. Group 4 received NAC (4800 mg/L) ad libitum 48 hours before the experiment. Blood and splenic pancreatic tissue samples were collected after 4hour of reperfusion. Serum amylase was determined and expression level of isoform GST-α was evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). Total pancreatic RNA (20ng) from all animals was subjected to qRT-PCR. Normalized qRT-PCR data were determined from the ratio of GST-α/β-actin values for each sample. RESULTS: Serum amylase levels were 6.11 (sd=0.55) mg/mL/min, 10.30 (sd=0.50) mg/mL/min, 9.77 (sd=1.24) mg/mL/min and 7.82 (sd=0.38) in Groups 1, 2, 3 and 4, respectively. There was an increase in serum amylase when compared group 1 with group 2 (p=0.0002) and a decrease when compared group 2 with group 4 (p=0.003). An increase in GST-α expression was observed in groups 3 and 4 when compared to group 2 (p=0.016). Conclusion: N-acetyl cysteine given 48 hours before experimental ischemia-reperfusion injury induction normalizes hyperamilasemia. This protective effect in pancreatic tissue under ischemia-reperfusion injury may be due to an increase in expression level of GST-α gene. Finally, NAC may have a potential benefit in graft acute pancreatitis related to ischemia-reperfusion injury.