An immunohistochemical study of the endocrine cells in the gastrointestinal mucosa of the Caiman latirostris.

Twelve endocrine cell types immunoreactive for either 5-hydroxytryptamine (5-HT), somatostatin, gastrin, motilin, neurotensin, bovine pancreatic polypeptide (BPP), avian pancreatic polypeptide (APP), pancreatic glucagon, enteroglucagon, glicentin, secretin or cholecystokinin (CCK) were found in gastrointestinal mucosa of Caiman latirostris. Moderate numbers of enteroglucagon-immunoreactive cells, a few 5-HT-, somatostatin- and motilin-immunoreactive cells and rare pancreatic glucagon-immunoreactive cells were found in the fundic stomach. Numerous gastrin-immunoreactive cells and moderate numbers of somatostatin- and motilin-immunoreactive cells were seen in the pyloric stomach. Moderate numbers of 5-HT-, gastrin-, motilin- and enteroglucagon-immunoreactive cells, a few somatostatin-, neurotensin- and BPP-immunoreactive cells, and rare APP-, pancreatic glucagon-, glicentin-, secretin- and CCK-immunoreactive cells were observed in the proximal intestine. Moderate numbers of 5-HT-immunoreactive cells, small to moderate numbers of neurotensin- and enteroglucagon-immunoreactive cells and occasional somatostatin-, motilin- and BPP-immunoreactive cells were seen in the distal intestine. Moderate numbers of neurotensin-immunoreactive cells and a few 5-HT-immunoreactive cells were found also in the cloaca. Cells immunoreactive for gastrin releasing polypeptide, bombesin and gastric inhibitory peptide were not observed in the caiman gastrointestinal epithelium. The differences in endocrine cell types between the caiman and alligator are discussed in terms of their topographic distribution.