Abstract
Serotonin (5-HT) isneurohormone with multiple effects in mammals and has its synthesis initiated from tryptophan by the enzyme tryptophan hydroxylase I (Tph1). It has been thought that 5-HT promotes the colon tumor development, although recent data have shown that it inhibits the formation of preneoplastic lesions in the colon. Unpublished results from my Young Investigator Awards (FAPESP…