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. A transient vimentin-immunoreactivity has also been detected within ductal cells in rat foetal pancreas. Here, we report that in rat pancreas an intense GFAP-like immunoreactivity is detectable within a sub-population of endocrine cells located in the periphery of the islet of Langerhans. In addition, staining appeared to be prevalently located in the apical pole of the cells. Two different polyclonal antibodies have been employed in the present study with analogous results. Staining of consecutive sections with anti-GFAP, anti-glucagon and anti-somatostatin antibodies demonstrates that GFAP-like immunoreactivity is present within glucagon-secreting cells. The relevance of this finding is discussed.