In order to gain additional insight into the functional role of sex steroid hormones in the choroid plexus, the present study compared gene expression patterns between sham and gonadectomized female/male rats choroid plexus. Overall design: For microarray analysis choroid plexus were collected from sham (control) and gonadectomized female and male rats. Equal amounts of RNA extract from the 3 pools of sham (control) or 3 pools of gonadectomized animals were used.