L-5-Hydroxytryptophan

5-hydroxy-L-Tryptophan (5-HTP) is an intermediate in the biosynthesis of serotonin from tryptophan.¹ When injected systemically in animals, 5-HTP is converted to serotonin and has both peripheral and central nervous system effects.^2,3,4 In ex vivo studies, 5-HTP can be metabolized to melatonin with circadian rhythmicity, using serotonin as an intermediate.⁵ 5-HTP can also be synthesized by gut microbiota and acts as an activator of the aryl hydrocarbon receptor.⁶

1.Martinez, A., Knappskog, P.M., and Haavik, J.A structural approach into human tryptophan hydroxylase and its implications for the regulation of serotonin biosyntheisCurr. Med. Chem.8(9)1077-1091(2001) 2.Haberzettl, R., Fink, H., and Bert, B.The murine serotonin syndrome - evaluation of responses to 5-HT-enhancing drugs in NMRI miceBehav. Brain Res.277204-210(2015) 3.Laporta, J., Moore, S.A.E., Weaver, S.R., et al.Increasing serotonin concentrations alter calcium and energy metabolism in dairy cowsJ. Endocrinol.226(1)43-55(2015) 4.Schmid, C.L., and Bohn, L.M.Serotonin, but not N-methyltryptamines, activates the serotonin 2A receptor via a β-arrestin2/Src/Akt signaling complex in vivoJ. Neurosci.30(40)13513-13524(2010) 5.Cahill, G.M., and Besharse, J.C.Circadian regulation of melatonin in the retina of Xenopus laevis: imitation by serotonin availabilityJ. Neurochem.54(2)716-719(1990) 6.Sridharan, G.V., Choi, K., Klemashevich, C., et al.Prediction and quantification of bioactive microbiota metabolites in the mouse gutNat. Commun.55492(2014)