Hidden face of the anterior pituitary

The traditional view holds that the anterior pituitary is an endocrine gland with a complex and heterogeneous distribution of cells throughout the parenchyma. Thus, a long-distance mode of intraorgan communication is not usually taken into account in our understanding of pituitary functioning. However, recent in situ pituitary studies have begun to unveil a hitherto unknown route of large-scale information transfer within the pituitary. Agranular folliculostellate cells – the sixth type of pituitary cell initially discovered almost half a century ago – are the functional units of a dynamically active cell network wiring the whole gland. Because folliculostellate cells communicate with their endocrine neighbors, this opens the door to considering the pituitary as a cellular puzzle more ordered than was first thought. Hence, cell networking within the pituitary gland could have a privileged role in coordinating the activities of distant cells in both physiological and pathological conditions. Pituitary functioning probably requires a fine-tuning of cellular signals that are coded in time and space within the parenchyma. The network of folliculostellate cells might have a crucial role in such processes.