Effects of co- exposure to heat and psychological stresses on serum levels of testosterone in male rats

The present study aimed to investigate the effect of co-exposure to heat stress as an environmental stressor and psychological stress on serum levels of testosterone in male rats.

This study was performed on 40 healthy adult male Wistar rats during a period of 40 days. The rats were evenly and randomly divided into three exposure groups and one control group. The rats in the heat stress group were exposed to 36 ° C and 20% humidity. The rats in psychological stress group was daily exposed to three types of stress: strobe light, cage tilt, and noise. The rats in co-exposure group also experienced both types of heat and psychological stresses.  Then, the level of testosterone was measured in all groups.

The results showed that the co-exposure group (4.20 ng/ml ±1.15) had lower hormone levels than the two exposure groups that were separately exposed to heat stress (4.35 ng/ml ± 1.15) and psychological stress (4.98 ng/ml ±1.51); while the level of hormone in the control group was 5.41 ng/ml ± 1.69 (P>0.05). The results of univariate analysis showed that the co-exposure group had the highest difference in hormone levels compared to the control group and the largest effect size.

In general, heat and psychological stress can each affect the level of testosterone as one of the components of reproduction system. However, co-exposure to these two types of stressors may lead to more severe effects on the testosterone level.