Glial fibrillary acidic protein (GFAP)-like immunoreactivity in rat endocrine pancreas

The study of intermediate filament expression in the pancreatic epithelium has been previously focused almost exclusively on cytokeratins. Transient v imentin immunoreactivity has also been detected in duct cells of rat fetal pancreas. Here we report that, in rat pancreas, intense GFAP-like immunorea ctivity is detectable in a subpopulation of endocrine cells located in the periphery of the islet of Langerhans. In addition, staining appeared to be preferentially localized to the apical pole of the cells. Two different pol yclonal antibodies were employed in this study, with analogous results. Sta ining of consecutive sections with anti-GFAP, anti-glucagon, and anti-somat ostatin antibodies demonstrates that GFAP-like immunoreactivity is present in glucagon-secreting cells. The relevance of this finding is discussed.