Molecularly defined serotonin (enterochromaffin) cells of the gut lining were distinguished by single-cell expression analysis, in situ hybridization, and immunohistochemistry into 14 topographically ...

Circulating serotonin is produced in the duodenum by enterochromaffin cells, specialized endocrine cells in the epithelia lining the gut, and functions within a specialized neuroendocrine network.