Changes in gene expression during Wolffian duct development

Background: Wolffian ducts (WDs) are the embryonic precursors of the male reproductive tract. Their development is induced by testosterone, which interacts with the androgen receptor (AR). The molecular pathways underlying androgen-dependent WD development are largely unknown. We aimed to identify AR target genes important in this process. Methods: RNA was isolated from rat WDs at E17.5 and E20.5. Affymetrix GeneChip expression arrays were used to identify transcripts up- or down-regulated more than 2-fold. Regulation of seven transcripts was confirmed using quantitative PCR. Results: Transcripts from 76 known genes were regulated, including modulators of insulin-like growth factor and transforming growth factor-β signalling. By controlling these modulators, androgens may indirectly affect growth factor signalling pathways important in epithelial-mesenchymal interactions and organ development. Caveolin-1, also upregulated, may play a role in modifying as well as mediating AR signalling. Differentiation of WD epithelium and smooth muscle, innervation and extracellular matrix synthesis were reflected in regulation of other transcripts. Several genes were previously suggested to be regulated by androgens or contained functional or putative androgen/glucocorticoid response elements, indicating they may be direct targets of androgen signalling. Conclusion: Our results suggest novel cohorts of signals that may contribute to androgen-dependent WD development and provide hypotheses that can be tested by future studies.