[Characterization of heavy metal secretory granules in the islet tissue of adult white rats by means of the light and electron microscopy, including the high voltage electron miscroscopy and the electron microanalysis (author's transl)].

The metal secretory granules of Langerhans' islets of white rats were examined after histochemical detection by sulfide silver staining method as well as by conventional electron microscopy and high voltage electron microscopy. Zinc and calcium were determined with electron probe x-ray-microanalysis. The metals are located at the inside of cytoplasmatic vacuoles, a result, we discuss in connection with the release of pancreatic hormones.