Production of serotonin by a transplantable strain of histamine-producing primary gastric carcinoid of Mastomys natalensis.
Two biochemically distinguishable transplantable tumor strains (A and B) were established from a primary gastric carcinoid of Mastomys secreting histamine alone. Strain A in the third generation acquired a new ability to produce serotonin [5-hydroxytryptamine (5-HT)] and retained endocrine activities to produce both histamine and 5-HT through the following subpassages, whereas strain B (like the primary tumor) continued to produce histamine alone. The findings were further supported by the immunohistochemical demonstration of 5-HT-containing tumor cells in strain A after generation 3 and the absence of such cells in strain B and also by the ultrastructural demonstration of tumor cells containing pleomorphic secretory granules in strain A after the third generation but not in strain B. Sixteen samples of Formalin-fixed, paraffin-embedded primary gastric carcinoids of Mastomys were stained by the same immunohistochemical method for 5-HT detection. The positively stained tumor cells were demonstrated in 4 tumor samples, though they were scantily distributed in tumor parenchyma except for 1 metastasizing tumor. 5-HT-producing tumor cells appeared through many proliferative cycles of the deranged histamine-producing cells. The endocrinologic similarity was noted between this transplantable tumor strain and a specific type of gastric carcinoid in humans, and the possible histogenesis of the latter tumor was discussed on the basis of data obtained from the present transplantation experiments.
D000818:Animals; D002276:Carcinoid Tumor / Q000378:metabolism* / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D005260:Female; D006632:Histamine / Q000652:urine; D006636:Histamine Release; D006897:Hydroxyindoleacetic Acid / Q000652:urine; D008854:Microscopy, Electron; D009115:Muridae; D009368:Neoplasm Transplantation; D012701:Serotonin / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000648:ultrastructure
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D006632:Histamine