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process. During the early development, the adenohypophysis anlage originates as a
placode in the nonneural ectoderm adjacent to the anterior neural plate (Fig. 3.1a).
Both the adenohypophysis placode and hypothalamic anlage interact with each
other. Accordingly, the thickened placode invaginates and subsequently detaches
from the oral ectoderm to form a hollowed vesicle termed “Rathke’s pouch” (Zhu
et al. 2007 ) (Fig. 3.1b). The molecular nature of this local inductive interaction dur-
ing this initial phase of pituitary formation has been intensively investigated, but
still remains elusive. Among them, FGF and BMP signals appear to be involved as
important factors (Takuma et al. 1998 ; Brinkmeier et al. 2007 ).
Fig. 3.1 Diagram of mouse pituitary development. (a) Dorsal view of neural plate and placodes.
(b) Sagittal view of pituitary embryogenesis
H. Suga and C. Ozone