Immunocytochemical study of endocrine cells in the gut of goldfish Carassius carassius (L) var auratus submitted to experimental lead intoxication

In the present study, the effects of experimental lead pollution on gut endocrine cells have been determined in the goldfish Carassius carassius (L.) var. auratus by immunocytochemical reactions. In the mucosa and submucosa, only vasoactive intestinal polypeptide- and 5-HT-like immunoreactive nerve fibers were observed. Endocrine cells displaying immunoreactivity against gastrin, CCK8, metenkephalin, bombesin, neuropeptide Y, pancreatic polypeptide, substance P, secretin, somatostatin and vasoactive intestinal polypeptide antibodies were detected. No immunoreactivity against glucagon, insulin and 5-HT antibodies was revealed in the endocrine cells. Some modifications appeared evident in the endocrine cells 48-96 h after lead intoxication, and can be summarized as follows: 1) discharge of secretory granules (secretin- and vasoactive intestinal polypeptide-like peptides), up to the extent that the cells appeared to be depleted of secretory material; 2) increase of immunoreactivity in the endocrine cells (met-enkephalin- and pancreatic polypeptide-like peptides) or in the frequency of positive cells (met-enkephalin-like peptide); 3) no variations (gastrin-, CCK8, bombesin-, somatostatin- and substance P-like peptides). The alterations were not enhanced by long term treatment. Nerve fibers did not show modifications.