Copulation modifies AR and ERα mRNA expression in the male rat brain

Background/AimsOne day after male sexual behavior [one ejaculation or copulation to satiety (ad libitum copulation during 4 h with the same female)] androgen receptor immunoreactivity (AR-ir) is decreased and estrogen receptor alpha immunoreactivity (ERα-ir) increased in various brain areas related with its control. Seven days after sexual satiety there was a limited recovery of sexual behavior accompanied by a partial recuperation in the AR-ir. In this study we evaluated if these changes in AR-ir and ERα-ir were paralleled by variations in their respective mRNA.MethodsSexually experienced male rats were sacrificed at different intervals: immediately, 24 h or seven days after sexual satiety or 24 h after one ejaculation. The changes in AR and ERα mRNA were analyzed by in situ hybridization using digoxigenine-labeled oligonucleotide probes in the MPOA, LSV and the bed nucleus of the stria terminalis, medial division, anterior (BSTMA).ResultsAR mRNA density was decreased in the MPOA and the LSV immediately and 24 h after one ejaculation or sexual satiety. Seven days after copulating to satiety, there was a recovery of AR mRNA. In the BSTMA the different behavioral conditions did not modify the AR mRNA expression. In the MPOA, LSV and BSTMA the ERα mRNA increased after a single ejaculation and at all intervals after sexual satiety.ConclusionIn some brain areas and after some intervals of sexual activity, the changes in steroid protein receptors expression seem to be consequence of parallel changes in the expression of the respective mRNA.

Research Highlights
► Sexual behavior decreased androgen receptor mRNA in mPOA, LSV but not in BSTMA.
► Copulation increased estrogen receptor α mRNA in mPOA, LSV and BSTMA.
► Most of these changes match with similar variations in respective proteins.
► No cumulative changes in ERα or AR mRNA cause the sexual satiety inhibition.
► Sexual activity affects a transcriptional process.