Discrete stages of anterior pituitary differentiation recapitulated in immortalized cell lines.

Targeted expression of oncogenes in transgenic mice can immortalize specific cell types to serve as valuable cultured model systems. Utilizing promoter regions from pituitary genes activated in the gonadotrope/thyrotrope lineage at discrete stages of development, we have demonstrated that targeted oncogene expression in transgenic mice can produce cell lines representing sequential stages of differentiation. Each cell line expresses a specific subset of the genes denoting differentiated function such as the subunits of the glycoprotein hormones, hormone receptors, and transcriptional regulatory proteins. These model systems have allowed detailed investigations into molecular and cellular mechanisms otherwise inaccessible in vivo or in complex primary pituitary cell cultures.