Effects of environmental stress on mRNA and protein expression levels of steroid 5α-Reductase isozymes in adult rat brain

Environmental stress conditions are important factors in human health and should be considered in the development of appropriate health policies, since they have been associated with psychological disorders and even with death. A link between stress and changes in 3α,5α-reduced neurosteroids has been reported. Steroid 5α-Reductase (5α-R) is the rate-limiting enzyme in the biosynthesis of 3α,5α-reduced neurosteroids. Using reverse transcription-polymerase chain reaction and immunohistochemistry, 5α-R isozymes (5α-R1 and 5α-R2) mRNA and protein levels were detected in prefrontal cortex of male and female rats after they underwent environmental stresses, i.e., excessive heat, artificial light, and the sensation of immobility in a small space, similar to those found in common workplace situations. Results showed significantly higher 5α-R2 mRNA and protein levels in environmentally-stressed versus control rats. Interestingly, a sexual dimorphism in 5α-R1 mRNA and protein levels was observed after environmental stress, with an increase in males and a decrease in females. This fact might explain gender differences in the incidence of some type of minor depression.