Figure 2.

Main signalling pathways and factors required during pituitary development. Opposing activities of BMP4 and SHH within the ventral diencephalon pattern this region and participate in correct morphogenesis of the infundibulum and in consequence positioning of RP. Within the infundibulum, BMP4 and FGF8, FGF10 and FGF18 are required for development of RP. In RP at 10.5 dpc, BMP2 is present and there is a uniform SMAD activation profile, while the FGF pathway is only activated dorsally (Davis et al. 2011). At this stage, different transcription factors required for RP progenitor proliferation and/or maintenance are ubiquitously expressed. Later, at 14.5 dpc, progenitors are confined around the RP lumen, while differentiating and differentiated cells away from the lumen define the developing anterior pituitary.