Pursuing the idea that additional TF could be co-opted for coordinating gene expression that would contribute not only to epithelial-cell death but also to an adaptation of the organ in general and the epithelium in particular to varying hormonal conditions, notably complete androgen deprivation, and that these changes increase the susceptibility to progression to CRPC, we performed gene expression profiling using DNA microarrays to identify TF associated with the most-regulated genes after androgen deprivation by surgical castration. We included in the analyses a group of rats that received a high dose of 17b-estradiol and a group of rats that were castrated and treated with E2. Inspired by the study of Yeh et al., we attempted to identify regulatory networks among the genes obtained from microarray data, by examining the relatedness between the regulated genes and structural signatures in their promoters. In a first approach, we identified all genes showing differential expression in each experimental group when compared to the controls. The differentially expressed genes were arranged into enrichment terms, and the resulting regulatory gene networks constructed were used for the identification of candidate TF. In a second approach, we examined the 3,000 bp proximal promoter of the ten most differentially expressed genes for the presence of putative transcription-factor binding sites, and determined their relative abundance with respect to the corresponding promoter regions of two internal control genes. The filtered TF were then validated by qRT-PCR and localized in the gland by immunohistochemistry. The expression pattern and tissue location of these TF appear to be important for the fine-tuning of prostate adaptation to the androgen-deprived environment. We found MYBL2 to be concentrated in the epithelial cells and discretely in the cell nucleus. GATA2, on the other hand, was found in both epithelial and stromal cells, with clear nuclear localization in non-castrated animals. The number of cells showing nuclear localization was reduced in animals examined 3 days after castration. EVI1 was found in both epithelium and stroma, and showed nuclear localization in the epithelium after castration. ELK1 showed a restricted stromal localization in morphologically recognized smooth-muscle cells. NFYB was detected in the nucleus of epithelial cells in non-castrated animals. The nuclear localization was partly lost after castration. Stromal cells were also positive for NFYB. NFkB1 was found in both epithelium and stroma in noncastrated and castrated animals. The epithelium also expressed RelA and RelB, which, similarly to NFkB1, were not responsive to castration in terms of epithelial/stromal distribution. In contrast, REL was expressed in the epithelium after castration and was found in the cell nucleus. Since nuclear translocation of this occurs upon activation, this location is a good indication that REL is activated after castration.