Histological and immunocytochemical study of the endocrine pancreas of the lizard Podarcis hispanica Steindachner, 1870 (Lacertidae).

The endocrine pancreas of the lizard Podarcis hispanica is described using light and electron microscopy. The endocrine pancreas of this reptile is located throughout the spleen side of the organ and consists of islet-like structures, small groups of two to five cells, and single scattered endocrine cells. The endocrine cells, including the islet-like structures, are not discrete units; on the contrary, they are intermingled with the endocrine component, both forming the glandular units. The endocrine islet-like structure shows a peculiar pseudoacinar pattern. The tridimensional reconstruction allows us to recognize the true structure of the glandular units. They are made up of two or three tubules closely arranged around a blood vessel, the endocrine component being disposed in the facing aspects of the tubules, around the vessel. Silver methods, Giemsa, and peroxidase-antiperoxidase techniques for light microscopy, immunogold, and routine methods for electron microscopy were used to demonstrate the regulatory peptide-producing cells present in the endocrine pancreas. Four major pancreatic endocrine cells, immunolocalized with the light and electron microscope, have been described: glucagon-containing cells (granules of 440 nm in diameter), insulin cells (400 nm), somatostatin cells (610 nm), and pancreatic polypeptide-containing cells (460 nm).