Figure 8. Signaling molecules and transcription factors involved in the development of the mouse anterior pituitary from Rathke’s pouch. In the anterior lobe somatotrophs, lactotrophs and caudally-placed thyrotrophs derive from a common lineage, determined by Prop-1 and Pit-1. Independent lineages are observed for a rostrally-placed group of thyrotrophs, corticotrophs, gonadotrophs and intermediate lobe melanotrophs. All cell types are committed to a specific lineage through activation of Notch signaling at the placodal stage. (Adapted from Cohen and Radovick, Endocrine Reviews 23: 431-442, 2002; Zhu X, Gleiberman AS, Rosenfeld MG, Physiol Rev 87: 933-963, 2007; Zhu X, Wang J, Ju B-G, Rosenfeld MG, Curr Op Cell Biol 19: 605-611, 2007).