Evidence for two secretory cell types in the Stannius bodies of the teleosts @entity22159 and XXXX .

@entity22159 @entity460 @entity14645 @entity2083
The Stannius bodies of @entity22159 and @entity2083 were ultrastructurally investigated after exposure of the fish to media of different osmolality and @entity460 content. In both species two structurally different secretory cell types are found. Type-1 cells predominate. They contain an extensive granular endoplasmic reticulum, some large Golgi areas, and secretory granules with a mean diameter of about 0.4 micron. These cells are activated by transfer of freshwater fish to seawater, but not by transfer to low- @entity460 seawater. Type-2 cells often contain cytoplasmic processes that penetrate between the type-1 cells and are ending on the basal lamina. In this contact area granule release takes place. Type-2 cells contain some strands of granular endoplasmic reticulum, several small Golgi areas, and secretory granules with a mean diameter between 0.15 and 0.20 micron. Type-2 cells are not activated after transfer of fish to seawater. In @entity22159 seawater exposure leads to a reduction of type-2 cells. The differences between the reactions of both cell types to different media point to functional differences between their secretory products. Type-1 cells may produce @entity14645 factor. It is concluded that type-2 cells are typical for freshwater fish or euryhaline fish spending part of their life cycle in freshwater. The proper function of these cells is unclear.
