Localization of Notch family members in the pituitary at p5. In situ hybridization for Notch2 (A and B), Hey1 (C and D), and Hes1 (E and F) reveals that Notch signaling components are mainly localized to cells surrounding the pituitary cleft. qRT-PCR comparing control and Notch2 cKO pituitaries at p1 shows specific and significant reductions in mRNA levels of Notch2 (G) and Hes1, Hey1, and Prop1 (H). *, P < .05; ***, P < .001. Bars, 50 μm. n = 3 to 4 (in situ hybridization) and n = 4 (qRT-PCR).