
Fig. 2. Pituitary organ size diminishes with reduced PITX2 dosage. (A) Diagram of pituitary morphology. INF, infundibulum, the prospective posterior lobe; INT, intermediate lobe; ANT, anterior lobe. Immunohistochemical examination shows that the expression of PITX1 (B) and PITX2 (C) overlaps in the anterior lobe and intermediate lobe, but not in the posterior lobe (D). Histological examination of E12.5 embryo sagittal sections of Pitx2 wild type (E), Pitx2neo/neo (F), Pitx2neo/ (G) and Pitx2/ (H) shows that the size of Rathkes pouch decreases as the Pitx2 level is reduced. Note that the Pitx2neo/ embryo has an intermediate pouch size.