Telotristat ethyl (LX1032) is a novel, orally-delivered inhibitor of tryptophan hydroxylase that reduces serotonin production.In Vivo: Telotristat ethyl (15, 50, 150, 300 mg/kg, po, qd) reduces serotonin content in the periphery, but not in the brain of the mice. Telotristat ethyl (200 mg/kg po, qd) prevents the increase in blood neutrophil counts that is observed after TNBS challenge, provides significant protection in a mouse model of inflammatory bowel disease. Telotristat ethyl (200 mg/kg po, qd) protects the mouse IBD model confirmed by histopathology evaluation. Telotristat ethyl (15, 50, 150, 300 mg/kg) depletes 5-HT from the jejunum but not the brain. But Telotristat ethyl (200 mg/kg, p.o.) does not deplete enteric neuronal serotonin (5-HT), or alter constitutive gastrointestinal motility in mice. Telotristat ethyl (200 mg/kg) alleviates the severity of trinitrobenzene sulfonic acid (TNBS)-induced colitis[2].