The anterior pituitary gland (adenohypophysis) is an endocrine organ which releases many hormones affecting growth, sexual development, metabolism and the system of reproduction. It consists of the anterior and the intermediate lobes. The anterior lobe is composed of five types of hormone-producing cells, S100β protein-positive cells (S100β
+ cells), endothelial cells and pericytes. S100β
+ cells have a star-like appearance and are interconnected by cytoplasmic processes and encircle hormone-producing cells or aggregate homophilically to form a central lumen in the anterior lobe. Based on these histological features, S100β
+ cells in the anterior lobe are commonly referred to as folliculo-stellate cells. They also appear to possess multifunctional properties. Considering their pleiotropic features, it is not surprising that S100β
+ cells are assumed to be heterogenous. By the observation of different markers, these cells were classified into subtypes such as stem cells, progenitor cells, epithelial cells, astrocytes and dendritic cells. Isolation and characterization of each heterogenous population is a prerequisite to clarify the functional character and origin of the cells. In this review, we described our method for separating the subtypes (dendritic cell-like type and others) of S100β
+ cells from the rat anterior lobe and summarized the results of our recent investigations.
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