Comparison of Lactate Threshold, Glucose, and Insulin Levels Between OLETF and LETO Rats After All-Out Exercise.

Otsuka Long-Evans Tokushima Fatty (OLETF) rats are an animal model for obesity and Non Insulin Dependent Diabetes Mellitus by hyperphagia. The lactate threshold (LT) is used to determinate aerobic capacity and exercise intensity in individuals. The purpose of this study was to determine whether velocity at the LT (VLT), glucose, and insulin levels of OLETF differs from Long-Evans Tokushima (LETO) rats after all-out exercise on treadmill running. In the results, we found that VLT level of OLETF rats (17.8 ± 1.39 m·min(-1)) was significantly lower than that of the LETO rats (20.5 ± 1.33 m·min(-1)). The blood glucose levels immediately after all-out exercise increased in OLETF (from 7.23 ± 0.36 to 9.38 ± 1.77 mmol·L(-1)) and decreased in LETO rats (from 6.36 ± 0.27 to 4.42 ± 0.71 mmol·L(-1)), and the insulin level was decreased in both the OLETF (from 34.4 ± 7.7 to 20.13 ± 8.63 µU·mL(-1)) and LETO (from 15.29 ± 2.6 to 5.72 ± 1.49 µU·mL(-1)) rats immediately after the all-out exercise, but the difference was not significant. Our results suggest that the different VLT, blood glucose and insulin levels should be considered to compensate for the differences between the OLETF and LETO rats. Moreover, the VLT will be a useful reference for the future studies on exercise training of OLETF rats. Key pointsThe VLT of OLETF was significantly lower than that of LETO rats.The changes of the blood lactate levels from rest to all-out exercise showed significant difference between OLETF and LETO rats.The result of low VLT in the OLETF compared to LETO rats implies that the application of relatively low exercise intensity is suitable for OLETF rats.The different VLT should be recognized to compensate for the differences between the OLETF and LETO rats.