tryptophan , 5-hydroxytryptophan , serotonin , n-acetylserotonin , melatonin , 5-hydroxyindoleacetic acid , n-acetyltransferase ( nat ) activity , and hydroxyindole-o-methyltransferase activity were measured by a combination of three techniques , which included microassays , radioimmunoassay , and high-performance liquid chromatography .
C0041249
tryptophan
C0000578
5-hydroxytryptophan