Classically, anterior pituitary cell types have been characterized and classified according to their hormone content and hormone secretion profile, except for the group of chromophobe cells. The main part of this chromophobe cell group for long was considered a coherent cell group, called the folliculo-stellate cells. Recent progress in pituitary cell biology not only demonstrated the functional heterogeneity of these folliculo-stellate cells, but also suggested a role for folliculo-stellate cells as tissue-specific stem cells. To corroborate these alleged stem cell properties, new techniques have been introduced, involving new cellular concepts in neuroendocrinology. The discovery of these new cell types and the discovery of hematopoietic progenitor cells homing at the anterior pituitary, once again raised the question of the embryo-logical origin of these (sub) groups of anterior pituitary cells. Meanwhile, advances in the study of signaling network connectivity, forwarded clear evidence of the interconnectedness of signaling networks and cell processes related to (de)differentiation, cell motility and neoplasm formation. Taking these data together, a more versatile picture of the cellular composition of the anterior pituitary arises, representing an interesting model for the study of cellular networks in normal development and during tumorigenesis.
Buy this Article