Endocrine cells of the gastroenteropancreatic system in Testudines A brief review

Enteroendocrine cells (EECs) are present throughout the digestive tract and synthesize various types of hormones that play important roles in gastrointestinal and systemic physiological regulation. These cells have been described in the gastrointestinal tract of several animals and can be classified according to their ability to retain silver salts, their communication with an animal's lumen and their immunoreactivity to specific molecules. Because the search for these cells has been important for understanding phylogenetic relationships, the objective was to perform a brief review of the existing literature on studies involving EECs in animals of the Testudines Order in order to help understand the digestive physiology of this group. Although there are a large number of species in this order, relatively few have their EECs details known, elucidated and well described. An improved understanding of these cells has enormous potential for functional and molecular studies, as well as having important implications for the conservation and comparative biology of species. We therefore believe that further research involving immunohistochemical assays as well also microscopic analysis (light and electron), is necessary in order to fill existing gaps.