Endocytosis of horse-spleen ferritin in the black tetra, Gymnocorymbus ternetzi (Characidae: Teleostei)

Abstract

The capability and capacity of various tissues in black tetra Gymnocorymbus ternetzi (Boulenger), family Characidae, to take up horse-spleen ferritin from the blood stream are described. In the head kidney from specimens injected intraperitoneally with horse-spleen ferritin, numerous large cells were tightly packed by yellow-brown granules when the period of time between injection and sacrifice was over 2 h. These cellular granules were tightly packed with Prussian blue precipitation in tissues treated with an acid ferrocyanide solution, i.e., they displayed a deep blue colour. Similarly, smaller cells were also observed in the trunk kidney, gills and peripheral connective tissue of the pancreas and spleen at this stage after ferritin injection, but they were always few in number. Yellow-brown granules or Prussian blue granules were not found in endothelial cell layers of heart and liver. We suggest that practically all clearance of the blood from foreign and scavenger macromolecules is performed by macrophages in the head kidney of the black tetra, whereas the spleen seems to function mainly as a reservoir for red blood cells in this species.