Journal Article

Immunohistochemical study of the six types of endocrine cells in the enteropancreatic system of the lizard Tropidurus torquatus (Squamata: Tropiduridae)

Sales, A, Mendes, A L S, Firmiano, E M S, Nascimento, A A, Cardoso, N N, Santos, M A J

2017

Overview

The present study investigates the aspects of endocrine cells secreting cholecystokinin, gastrin, insulin, glucagon, somatostatin and serotonin in the enteropancreatic system of Tropidurus torquatus. The specimens were collected in Marambaia Island, Sepetiba Bay, Rio de Janeiro State, Brazil. The animals’ intestine and pancreas were removed, fixed, processed and then subjected to immunohistochemical techniques. Three cell types, immunoreactive (IR) to gastrin, cholecystokinin-8 and serotonin, were identified in the intestinal mucosa. Serotonin was found in the small and large intestines, whereas gastrin and cholecystokinin-8 cells were only observed in the large intestine of T. torquatus. Glucagon, somatostatin and insulin were not observed in the intestines at all. Only glucagon, somatostatin and insulin were identified in the pancreas of the studied lizards. The dorsal lobe showed a large number of endocrine cells scattered throughout the exocrine parenchyma and in the exocrine duct walls. The present study shows that the intestine and pancreas of T. torquatus hold most of the regulatory peptides, presenting a structure similar to that in other vertebrates such as birds and mammals. The endocrine cells identified in the lizards’ enteropancreatic system evidences the good phylogenetic preservation of the regulatory peptides’ molecular structure.

• Publisher: Taylor & Francis Ltd
• Subject: Cholecystokinin / Gastrin / Glucagon / Immunohistochemistry / Insulin / Large intestine / Mucosa / Pancreas / Parenchyma / Peptides / Phylogeny / Preservation / Serotonin / Somatostatin / Tropidurus torquatus