In the latest of a series of remarkable studies, researchers
from the RIKEN Center for Developmental Biology in Kobe, Japan
report that embryonic stem cells grown under special conditions
can spontaneously organize themselves into a partial pituitary
gland that is fully functional when transplanted into mice. Over
the past four years, Yoshiki Sasai and his colleagues of RIKEN's
Organogenesis and Neurogenesis Group have developed a novel cell
culture technique for growing embryonic stem (ES) cells in
floating three-dimensional aggregates. In their new study,
published recently in Nature, they used it to grow mouse ES
cells and then altered the culture conditions to mimic the
chemical environment that gives rise to the adenohypophysis, or
anterior pituitary. Development of the adenophyophysis requires
interactions between two different types of tissue – the oral
ectoderm, which goes on to form the skin inside the mouth, and
the hypothalamic neuroectoderm, which generates a small
structure called the hypothalamu