<prompt> Enterochromaffin Cells in GIT secreteSerotoninHistamineBothNone  <response>: More than 15 types of hormone-secreting enteroendocrine cells have been identified in the mucosa of the stomach, small intestine, and colon. Many of these secrete only one hormone and are identified by letters G cells, S cells, etc. Others manufacture Serotonin or Histamine and are called enterochromaffin or ECL cells. 