Identification of the pituicytes as astroglial cells by indirect immunofluorescence-staining for the glial fibrillary acidic protein.

Glia cells of rat neural lobes (pituicytes) were stained in thin sections (6 micrometers) by the indirect immunofluorescence technique for the glial fibrillary acidic protein (GFA), the S-100 protein and fibronectin. The positive strong GFA-staining of the pituicytes demonstrates their astroglial character. Fibronectin was located along the blood capillaries. After six days of implantation of the neural lobes under the kidney capsule of an acceptor rat, the stained fibronectin was augmented and present in a fibrillar network scattered over the tissue; the GFA-staining remained positive, however. The astroglial character of pituicytes was apparently retained in the implantation conditions, whereas neurosecretory axons had already disappeared. No S-100 protein could be unambiguously detected in the glia cells with the antibody employed.