Molecular mechanisms of pituitary differentiation and regulation: implications for hormone deficiencies and hormone resistance syndromes.

During the last century, the questions posed by scientists and clinicians on pituitary function have led to new concepts about the mechanisms of hormone action and cell differentiation. In particular, the advent of molecular genetics and the cloning of pituitary hormone coding genes followed by discovery of their regulators during the last 20 years has provided tremendous insight into the pathophysiological bases of hormone deficit and excess, as well as offering novel therapeutic opportunities. Most insight was gained through the identification of transcription factors that control the program of pituitary organogenesis and cell differentiation; it is indeed the normal developmental program controlled by these transcriptional regulators that is perturbed in inherited forms of hormone deficiency. This review will summarize our current understanding of these processes and their implications for hormone deficiency and hormone resistance syndromes from a developmental perspective.