title: The occurrence, synthesis and metabolism of 5-hydroxytryptamine and 5-hydroxytryptophan in the cestode Hymenolepis diminuta: a high performance liquid chromatographic study.
abstract: The biosynthesis and metabolism of 5-hydroxytryptamine (serotonin; 5-HT) in the cestode Hymenolepis diminuta was investigated by High Performance Liquid Chromatography (HPLC). Incubation of intact H. diminuta in [3H]tryptophan resulted in substantial radioactivity recovered in 5-HT, 5-hydroxytryptophan (5-HTP), and 5-hydroxyindoleacetic acid (5-HIAA). Furthermore, the tissue levels of 5-HT and 5-HTP, as determined by HPLC with electrochemical detection, were significantly depressed when the animals were deprived of tryptophan. On the other hand, the tissue levels of 5-HTP were significantly increased following incubation with the 5-HTP decarboxylase inhibitor m-hydroxybenzylhydrazine. The synthesis and metabolism of 5-HT are discussed in the light of 5-HT as a physiological transmitter in H. diminuta.
mesh_terms: D006916:5-Hydroxytryptophan / Q000096:biosynthesis / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry; D006834:Hydrazines / Q000494:pharmacology; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D006926:Hymenolepis / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000096:biosynthesis / Q000378:metabolism*; D014364:Tryptophan / Q000378:metabolism
chemical_list: D006834:Hydrazines; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D014364:Tryptophan; C004297:3-hydroxybenzylhydrazine; D006916:5-Hydroxytryptophan