An enzymatic preparation from human brain converts tryptamine to tryptoline (9H-1,2,3,4-tetrahydropyrido(3,4-b)indole) in the presence of 5-methyltetrahydrofolic acid. Similarly, N-methyltryptamine and 5-hydroxytryptamine yield 1-methyltryptoline and 5-hydroxytryptoline, respectively. Neither in vitro nor in vivo formation of these compounds by human tissues has been described.

We describe a new cation-exchange fluorometry procedure for separation and measurement of three 5-hydroxyindole metabolites of tryptophan in blood. The metabolites are detected and measured via the fluorescence emitted in the visible region when the separated metabolite is added to a hydrochloric acid-ascorbic acid mixture. The assay requires only 30 mm and is both selective and sensitive. The ...