Abstract
Serotonin (5-HT) is neurohormone with multiple effects in mammals. The intestinal 5-HT synthesis is initiated by the enzyme tryptophan hydroxylase I (Tph1) activity on tryptophan. This neuropeptide is believed to promote colon cancer. However, our unpublished findings (FAPESP 2014/ 06428-5) demonstrate that this neurohormone inhibits not only the formation of colon preneoplastic lesions b…