title: L-Tryptophan action on hepatic RNA synthesis and enzyme induction.
abstract: L-Tryptophan increases the activity of hepatic amino acid metabolizing enzymes, affects gluconeogenesis and displays a modulatory effect on several enzymes connected with RNA synthesis. The underlying mechanism differ in individual cases and result in both an increase of enzyme synthesis de novo and a decrease of enzyme degradation. Tryptophan displays a unique effect causing aggregation of hepatic polyribosomes connected with enhanced protein synthesis and preceded by a higher transport of poly (A) messenger RNA from the nucleus to the cytoplasm. The variety of rather specific effects mediated by tryptophan brings to mind hormonal action and the existence of specific tryptophan receptors is predicted.
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects*; D005943:Gluconeogenesis / Q000187:drug effects; D012695:L-Serine Dehydratase / Q000096:biosynthesis; D008099:Liver / Q000378:metabolism*; D011132:Polyribosomes / Q000187:drug effects / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D012313:RNA / Q000096:biosynthesis*; D014158:Transcription, Genetic / Q000187:drug effects*; D014364:Tryptophan / Q000494:pharmacology*; D014366:Tryptophan Oxygenase / Q000096:biosynthesis; D014444:Tyrosine Transaminase / Q000096:biosynthesis
chemical_list: D000596:Amino Acids; D012313:RNA; D014364:Tryptophan; D014366:Tryptophan Oxygenase; D014444:Tyrosine Transaminase; D012321:DNA-Directed RNA Polymerases; D012695:L-Serine Dehydratase