An immunocytochemical and ultrastructural study of endocrine cells in the gut of a teleost fish, Sparus auratus L.

Endocrine cells in the gut of Sparus auratus L. (gilt-head sea bream) have been demonstrated by immunocytochemical and electron microscopic techniques. Cells showing somatostatin and gastrin-like immunoreactivity were found in the depth of the gastric folds and in the upper part of the stomach glands while substance P immunoreactive cells were present between the upper epithelial cells of the gastric folds. Cells showing gastrin, substance P, pancreatic polypeptide, cholecystokinin, and Met-enkephalin immunoreactivity were observed in the intestinal mucosa scattered between epithelial cells. Eight types of endocrine cells were ultrastructurally characterized by the shape, size, and electron density of their respective secretory granules. A tentative correlation between these diverse cell types and those identified by immunocytochemical techniques has been established.