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

Abstract

Introduction: 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. Materials and Methods: 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. Results: 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. Conclusion: 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.