Detection of estrogen receptor alpha and beta messenger ribonucleic acids in adult gonadotropin-releasing hormone neurons

The behavior of the gonadotropin-releasing hormones (GnRH) neurons controll ing fertility is dependent upon cyclic fluctuations in circulating concentr ations of estrogen. However, the nature of estrogen action upon these cells has remained controversial due to their dispersed distribution within the brain, and evidence indicating that they do not express nuclear estrogen re ceptors (ERs) in vivo. We report here an acute brain slice preparation that enables individual living GnRH neurons to be identified within the mouse b rain and show, using single cell multiplex RT-PCR, that the greater than 50 % of GnRH neurons in adult and prepubertal females contain ER alpha messeng er RNA. Approximately 10% of GnRH neurons contained ER beta transcripts tha t were, always coexistent with ER alpha. Single cell RT-PCR analysis of non GnRH cells located in the medial preoptic area revealed a similar coexpress ion pattern of ER alpha and ER beta transcripts. In contrast, single striat al cells were not found to contain ER beta despite ER alpha being present i n approximately 25% of cells. The analysis of single GnRH neurons in cyclin g female mice revealed that the detection of ER alpha and ER beta transcrip ts was lowest on proestrus (ER alpha, 18% of all GnRH neurons; ER beta, 0%) compared with diestrus (44% and 6%) and estrus (75% and 19%, respectively) . Using a novel approach that enables single cell RT-PCR analysis of GnRH n eurons, we present here evidence for the cyclic expression of ER alpha and ER beta messenger RNAs within prepubertal and adult female GnRH neurons.