Biological Properties of a Transplantable Islet-cell Tumor of the Golden Hamster: III. Electron Microscopic Studies

This paper describes the ultrastructure of a transplantable islet cell tumor of the hamster. No ultrastructural similarities with normal A or B pancreatic cells were noted. Signs of active metabolism and protein synthesis are the outstanding features of this tumor. The absence of typical β granules and the presence of some peculiar structures are discussed in the light of the demonstrated insulin-producing property of the tumor.