Androgen receptor mRNA is inversely regulated by testosterone and estradiol in adult mouse brain.

Androgen receptor (AR) is expressed in different tissues including the brain and is under regulation by sex steroid hormones. It mediates the action of androgen which plays a key role in learning, memory, and other brain functions that deteriorate with increasing age. We have correlated the expression of AR mRNA with its promoter methylation and their regulation by testosterone and estradiol in the brain cortex of adult and old male and female mice. Results revealed that (i) AR mRNA expression was significantly higher in male than in female mice. (ii) In both sexes, AR mRNA level was down-regulated by testosterone in adult and old, but up-regulated by estradiol only in adult mice. (iii) Methylation of AR core promoter was increased by testosterone, but decreased by estradiol. These findings show that AR mRNA expression and its core promoter methylation are inversely regulated by testosterone and estradiol in the adult mice brain cortex. Such regulation of AR expression might influence androgen action during aging of the mice brain.