| 3. Pituitary Physiology. |  |
This research area is not related to cancer chemoprevention or neuroprotection but to Anterior Pituitary Cells as a model of cell plasticity. This is a long term area of interest for us, although in the last few years we have focused on the above two research lines. The anterior pituitary is made up of 5 different cell types. Each cell type is characterised by storage of a particular anterior pituitary hormone and expression of a particular plasma membrane receptor for a hypothalamic releasing factor. However, we have discovered that a significant population of anterior pituitary cells do not fit this phenotypic clasification. Instead, around 30% of the cells present a rather mixed phenotype and are able to store multiple anterior pituitary hormones (polyhormonal cells), express multiple receptors for hypothalamic releasing hormones (multiresponsive cells) or both. These multifunctional cells are responsible for the so-called paradoxical secretion (hormone release evoked by a non related hypothalamic releasing factors) and are particularly abundant in human pituitary adenomas and in normal mouse or rat pituitaries during puberty. The specific physiological role of multifunctional anterior pituitary cells is unknown but likely contributes to pituitary plasticity and endocrine events along life.