An Ultrastructural Study of the Islet Cell Tumor of The Golden Hamster[*]

Abstract

An electron microscopic study of the transplantable islet cell tumor of the golden hamster was performed on tumor tissue obtained 3-9 weeks after transplantation. In addition to features previously observed in similar studies, tumor cells were found to contain elongated giant mitochondria which were characteristically associated with long profiles of the rough endoplasmic reticulum and, in some instances, were grouped to form circular multi-mitochondrial complexes. All tumor cells contained a variable number of secretory granules. Within any given cell these granules formed a morphologically heterogeneous population similar to that seen in certain catecholamine-producing cells. Although the ultrastructural appearance of individual secretory granules was reminiscent of the specific secretory granules of normal pancreatic endocrine cells, no cells containing one specific type of granules could be identified. The findings are discussed in the light of cytochemical and biochemical findings indicating the presence of insulin, glucagon and catecholamines in these tumors.

Key words

Islet Tumor - Golden Hamster - Insulin Producing Tumor - Glucagon-Producing Tumor - Catecholamine Producing Tumor - Secretory Granules - Giant Mitochondria - Electron Microscopy

1 This study was supported by Grants Nr. 3154.69, 3299.70 and 3384.70 from the Fonds National Suisse de la Recherche Scientifique, Berne, Switzerland.

1 This study was supported by Grants Nr. 3154.69, 3299.70 and 3384.70 from the Fonds National Suisse de la Recherche Scientifique, Berne, Switzerland.

2 Chargé de Recherche of the Fonds National Belge de la Recherche Scientifique, Brussels, Belgium.