The choroid plexus (CP) produces cerebrospinal fluid (CSF) and forms the blood-CSF barrier, being involved in the maintenance of the extracellular milieu of the brain and secretion of several neuroprotective factors. There are several experimental evidences showing that androgens enhance cognition and act as potential protective factors against Alzheimers Disease. It has been shown that testosterone exerts neuroprotective actions against oxidative stress, apoptosis, and against the toxicity of β-amyloid, all via androgen receptor (AR). The AR has been identified in several regions of the central nervous system: the medial preoptic, arcurate, and ventromedial nuclei of the hypothalamus, in the medial nucleus of the amygdala, in the CA-1 hippocampus and the cortex, but not in the CP. In a first approach to study if the neuroprotective effects of CP are mediated by androgens and AR we investigated the presence of AR mRNA and protein in rat CP. Adult animals were euthanized and CPs were collected and frozen at −80 °C or fixed with 4% paraformaldehyde in PBS. The presence and levels of AR protein in the CP were studied by immunohistochemistry and Western blot, and the mRNA expression of AR in the CP was analysed by RT-PCR. The obtained results clearly demonstrate the presence of AR mRNA transcripts and protein in the rat CP with the protein levels in CP slightly higher than those found in prostate, testis, epididymis, and liver. Therefore, it is likely that some of the neuroprotective proteins secreted by the CP may also be regulated by androgens.
Acknowledgements: This work was supported by grant POCI/SAU-NEU/55380/2004 from FCT