Background: Considering to the frequency of occurrence of hypoglycemia in diabetes, alternative substrates for glucose play an important role in maintaining brain metabolism. The aim of the present study was to investigate the long-term effects of endurance training on brain lactate uptake during hypoglycemia in type 1 diabetic rats.

Materials and Methods: In this experimental study, seventy-two male Wistar rats were equally divided into four groups: Control, Trained, Diabetic control and Diabetic trained. Diabetes was induced by intraperitoneally injection of streptozotocin. After 8 weeks of endurance training, Hypoglycemia was induced by an intraperitoneally injection of insulin. One-half hours after hypoglycemia, lactate (4 mmol/kg) was injected intraperitoneally into animals. Animals were killed at intervals of 10, 20, and 30 min after injection, plasma and brain concentration of lactate and glucose were measured.

Results: A significant difference was found for plasma lactate concentration at intervals 20 (p<0.05) and 30 (p<0.05) between healthy groups and also between diabetic groups (p<0.05). Thirty minutes after injection, significant increase in brain lactate concentration was found between control and trained (p<0.05) and control diabetic and diabetic trained (p<0.05). Brain/plasma ratio of lactate had a similar pattern with brain lactate concentration. Increase in brain lactate concentration had no effect on decreased level of brain glucose concentration.

Conclusion: Endurance training can increase the brain lactate uptake of diabetic rats during hypoglycemia.