Plasma testosterone of rats subjected to immobilization stress and/or HCG administration.

The effect of immobilization stress (IMO) on the plasma testosterone level in rats has been investigated. Plasma testosterone was not changed after 10 or 20 min IMO for 3 consecutive days as compared to nonstressed animals and the 10-min trial was without effect even if it was applied daily for 42 days. Thre days IMO for 60 min caused a significant hormone decrease, which was even more pronounced after 3 or 42 days IMO for 120 min. The administration of HCG to rrats immobilized 3 days for 120 min resulted in the increase of testosterone, however, the final level was significantly lower in comparison to nonstressed controls.