In vitro activity: Telotristat (formerly known as LP-778902) is the active metabolite of LX1606 (Telotristat etiprate) which is an orally bioavailable, small-molecule, tryptophan hydroxylase (TPH) inhibitor with potential an in vivo IC50 of 0.028 μM and with antiserotonergic activity. Telotristat has activity in controlling diarrhea associated with carcinoid syndrome. Telotristat acts by inhibiting the enzyme tryptophan hydoxylase (TPH) and reduces serotonin production both inside and outside the GI tract without affecting brain serotonin levels. Blocking peripheral serotonin synthesis by telotristat reduces severity of both chemical- and infection-induced intestinal inflammation.

Kinase Assay: Telotristat (formerly known as LP-778902) is the active metabolite of LX1606 (Telotristat etiprate) which is an orally bioavailable, small-molecule, tryptophan hydroxylase (TPH) inhibitor with potential an in vivo IC50 of 0.028 μM and with antiserotonergic activity.

Cell Assay: BON CBA cells are grown in equal volume of DMEM and F12K with 5% bovine serum for 3-4 hours (20 K cell/well) and telotristat is added at a concentration range of 0.07 to 50 μM. The cells are incubated at 37°C overnight. 50 μM of the culture supernatant is then taken for 5HTP measurement. The supernatant is mixed with equal volume of 1M TCA, then filtered through glass fiber. The filtrate is loaded on reverse phase HPLC for 5HTP concentration measurement. The cell viability is measured by treating the remaining cells with Celltiter-Glo Luminescent Cell Viability Assay.