Immunohistochemical localization of basic fibroblast growth factor in cultured rat astrocytes and oligodendrocytes

The distribution of basic fibroblast growth factor in cultured astrocytes and oligodendrocytes was examined using immunocytochemistry. The results demonstrate a localization of basic fibroblast growth factor immunoreactivity predominantly in astrocyte nuclei at all stages of differentiation. Cytoplasmic and process staining was best detected during early stages of differentiation, under normal growth conditions or as a result of treatment with dibutyryl cyclic adenosine monophosphate. Astrocytes at all stages of differentiation bound antibody-complexed bFGF, suggesting the presence of cell-associated low affinity binding sites for the growth factor. Our studies also show the presence of immunoreactivity for basic fibroblast growth factor in process-bearing oligodendrocytes. These results suggest a role for endogenous basic fibroblast growth factor in astrocyte and oligodendrocyte growth and function.