Establishment of a folliculo-stellate-like cell line from a murine thyrotropic pituitary tumor.

An isologously transplantable mouse thyrotropic pituitary tumor (TtTb) that had been induced by radiothyroidectomy was found to form lobules composed of parenchymal glandular cell elements. The surfaces of these lobules were covered by stellate cells bearing long processes that gave a strong immunopositive reaction with a specific antiserum against glial fibrillary acidic protein (GFAP). GFAP was also positive in pituitary folliculo-stellate cells (FS cells). Since in the anterior pituitary gland, no other cellular component showing positive staining with anti-GFAP antibody was observed, it seems probable that the GFAP-positive cells in the thyrotropic tumor are related to the FS cells in the anterior pituitary. Upon cultivation of the thyrotropic tumor, cells with long processes appeared. These cells showed strong staining for GFAP and were dependent on basic fibroblast growth factor for cell growth. By repeated passage, the GFAP-positive cells became a stably growing immortal cell line, which was tentat...