Post-ischemic injury is one of the most important problems affecting successful organ procurement and transplantation. The present study was performed to determine whether alpha-tocopherol can protect the endocrine function of pancreatic grafts against ischemia-reperfusion injury during rat heterotopic pancreatic transplantation. Rats with streptozotocin-induced hyperglycemia were used as recipients. The donor pancreas was removed and subjected to warm ischemia at 37 degrees C for 30, 60, 90 and 120 min, and then transplanted into a recipient. A 30-min period of warm ischemia did not impair the endocrine function of the pancreatic grafts, which was assessed by measuring the blood glucose levels and glucose decay constants (K), and a 60-min period of warm ischemia was considered to be the critical period for reversible tissue damage. Pretreatment with alpha-tocopherol (20 mg/kg/day, i.v.) for seven days before graftectomy significantly decreased blood glucose levels to less than 200 mg/dl and significantly increased K values in the recipient rats after transplantation when compared with placebo pretreatment. These results suggest that alpha-tocopherol pretreatment can protect the endocrine function of pancreatic grafts against injury due to warm ischemia followed by reperfusion.