1. Introduction
As a member of the POU-domain family gene,
POU1F1 (also named PIT-1 or GHF-1) is mainly
expressed in the pituitary and its expression is necessary
for the normal differentiation, development and survival
of three adenohypophysis cell types (thyrotrophs,
somatotrophs and lactotrophs) (Li et al., 1990). It is also
a positive regulator for growth hormone (GH), prolactin