Effects of Tribulus terrestris L. saponins on exercise performance in overtraining rats and the underlying mechanisms
Liang Yin Received February 15, 2016. Canadian Journal of Physiology and Pharmacology
The objective of this study was to determine the effects of Tribulus terrestris L. (TT) saponins on exercise performance and the underlying mechanisms. Rat overtraining model was established and animals were treated with TT extracts (120 mg/kg body weight) 30 min before each training. Serum levels of testosterone, corticosterone, and levels of androgen receptor (AR) and insulin growth factor-1 receptor (IGF-1R) in liver, gastrocnemius and soleus were determined by ELISA and Western blot.
Treatment of rats with TT saponins significantly improved the performance of the overtraining rats reflected by the extension of the time to exhaustion, with a concomitant increase in body weights, relative weights and protein levels of gastrocnemius. Overtraining alone induced a significant decrease in serum level of testosterone. In contrast, TT saponins treatment dramatically increased serum level of testosterone in overtraining rats to about 150% of control and 216% of overtraining group, respectively. In addition, TT saponins resulted in a further significant increase in AR in gastrocnemius and significantly suppressed overtraining-induced increase in IGF-1R in liver.
These results indicated that TT saponins increased performance, body weight and gastrocnemius weight of rats undergoing overtraining, which might be attributed to the changes in androgen-AR axis and IGF-1R signaling.