Human anterior hypophysis (pituitary gland), light micrograph. The sample has been stained with an immunohistochemical technique for glial fibrillary acidic protein (GFAP). A non-hormone-secreting cell type with a supporting role is found in the adenohypophysis. They are the folliculo-stellate cells, so called because they have extensions that give them a stellate appearance. These cells possess immunopositive filaments for the GFAP, a protein characteristic of astrocytes.