LP-533401 is a Tryptophan hydroxylase 1 inhibitor that regulates serotonin production in the gut.

LP-533401 completely inhibits serotonin production in Tph1–expressing cells (RBL2H3 cells) at a dose of 1 μM.

西域 has not independently confirmed the accuracy of these methods. They are for reference only.

Oral administration once daily for up to 6 weeks of this small molecule prevents the development of and fully rescues, in a dose-dependent manner, osteoporosis in ovariectomized rodents because of an isolated increase in bone formation. Pharmacokinetic studies in rodents show that LP-533401 level in the brain is negligible following oral administration, indicating that it is virtually unable to cross the blood-brain barrier. Mice treated repeatedly with LP-533401 (30–250 mg/kg per day) exhibit marked 5-HT content reductions in the gut, lungs, and blood, but not in the brain. After a single LP533401 dose (250 mg/kg), lung and gut 5-HT contents decrease by 50%, whereas blood 5-HT levels remain unchanged, suggesting gut and lung 5-HT synthesis. Adult, healthy mice treated with the Tph-1 inhibitor LP-533401 show 30% decrease in circulating serotonin levels, with a consequent 30% increase in osteoblast numbers. Administration of LP533401 to mice injected with EL4 cells inhibits the decrement in osteoblast numbers and trabecular bone volume, prolongs survial, and decreases leukemic infiltration.

西域 has not independently confirmed the accuracy of these methods. They are for reference only.

Oral administration once daily for up to 6 weeks of this small molecule prevents the development of and fully rescues, in a dose-dependent manner, osteoporosis in ovariectomized rodents because of an isolated increase in bone formation. Pharmacokinetic studies in rodents show that LP-533401 level in the brain is negligible following oral administration, indicating that it is virtually unable to cross the blood-brain barrier. Mice treated repeatedly with LP-533401 (30–250 mg/kg per day) exhibit marked 5-HT content reductions in the gut, lungs, and blood, but not in the brain. After a single LP533401 dose (250 mg/kg), lung and gut 5-HT contents decrease by 50%, whereas blood 5-HT levels remain unchanged, suggesting gut and lung 5-HT synthesis. Adult, healthy mice treated with the Tph-1 inhibitor LP-533401 show 30% decrease in circulating serotonin levels, with a consequent 30% increase in osteoblast numbers. Administration of LP533401 to mice injected with EL4 cells inhibits the decrement in osteoblast numbers and trabecular bone volume, prolongs survial, and decreases leukemic infiltration.

西域 has not independently confirmed the accuracy of these methods. They are for reference only.

• . Yadav, V.K., et al. Inhibition of gut-derived serotonin synthesis: A potential bone anabolic treatment. Nat. Med. 16(3), 308-312 (2010).

  . Abid S, et al. Inhibition of gut- and lung-derived serotonin attenuates pulmonary hypertension in mice. Am J Physiol Lung Cell Mol Physiol. 2012 Sep 15;303(6):L500-8.  [Content Brief]

  . Krevvata M, et al. Inhibition of leukemia cell engraftment and disease progression in mice by osteoblasts. Blood. 2014 Oct 30;124(18):2834-46.  [Content Brief]