抄録
We examined the production site of the resident intraperitoneal free cells of red sea bream Pagrus major, histologically and electron microscopically. There were many large round cells in mesenteriolum and the adjacent coelomic space near head kidney. Electron microscopical observation showed that the large round cells observed in the mesenteriolum and the adjacent coelomic space were a few heterophilic granulocytes and abundant large cells with similar morphologies of those observed in the abdominal cavity. In the mesenteriolum and the adjacent coelomic space, there were a few fibroblastic cells with many oval granular or vacuole-like structures, which had morphological similarity to the granules of peritoneal large cells. There were abundant round cells in mesenteries, most of which were heterophilic granulocytes. The 5-bromo-2'-deoxyuridine incorporation experiment revealed that these cells observed in the interstitial tissue were not aged but the young cells within 4 days after cell division. The results obtained in this study suggest that mesenteriolum and the adjacent coelomic space near head kidney are one of the pathways of granulocytes and large cells to abdominal cavity and provides the field of large cell production.
