Melano-macrophage centres and endocytic cells in kidney and spleen of pearl gouramy and platyfish (Anabantidae, Poeciliidae: Teleostei).

The structure and putative cellular content of melano-macrophage centres (MMCs) and single macrophages in kidney and spleen of two teleosts, pearl gouramy Trichogaster leeri (Bleeker) and platyfish Xiphophorus maculatus (Günther), are described and compared. The MMCs were confined to the haemopoetic tissue in both species, and were markedly more prominent in pearl gouramy than in platyfish. They were rich in iron-compounds, probably haemosiderin, in the former species, whereas they contained mainly iron-free pigments, probably lipofuscin, in the latter species. We suggest that the kidney and spleen MMCs are involved in the regular storage, relocation and recycling of iron-compounds of effete or damaged red blood cells in healthy pearl gouramies, whereas they function more or less as a deposit for undegradable and potentially harmful iron-free cell debris in the corresponding organs in healthy platies. Numerous single macrophages took up much intraperitoneally injected horse ferritin in the kidney and spleen haemopoetic tissue in platies, whereas these cells contain much iron-containing pigment, probably haemosiderin, in the control pearl gouramies. We suggest that these cells are able to play a role in cleansing the circulation of foreign macromolecules and particles in platies, whereas they are mainly involved in the regular uptake of scavenger iron-containing compounds in pearl gouramies.