title: Tryptophan and tyrosine catabolic pattern in neuropsychiatric disorders.
abstract: Catabolism of tryptophan and tyrosine in relation to the isoprenoid pathway was studied in neurological and psychiatric disorders. The concentration of trytophan, quinolinic acid, kynurenic acid, serotonin and 5-hydroxyindoleacetic acid was found to be higher in the plasma of patients with all these disorders; while that of tyrosine, dopamine, epinephrine and norepinephrine was lower. There was increase in free fatty acids and decrease in albumin (factors modulating tryptophan transport) in the plasma of these patients. Concentration of digoxin, a modulator of amino acid transport, and the activity of HMG CoA reductase, which synthesizes digoxin, were higher in these patients; while RBC membrane Na+-K+ ATPase activity showed a decrease. Concentration of plasma ubiquinone (part of which is synthesised from tyrosine) and magnesium was also lower in these patients. No morphine could be detected in the plasma of these patients except in MS. On the other hand, strychnine and nicotine were detectable. These results indicate hypercatabolism of tryptophan and hypocatabolism of tyrosine in these disorders, which could be a consequence of the modulating effect of hypothalamic digoxin on amino acid transport.
authors.affiliation: Department of Neurology, Medical College, Trivandrum, and Metabolic Disorders Research Centre, Puliyarakonam, Trivandrum, India.
authors.forename: A
authors.initials: A
authors.lastname: Ravikumar
authors.forename: K V
authors.initials: KV
authors.lastname: Deepadevi
authors.forename: P
authors.initials: P
authors.lastname: Arun
authors.forename: V
authors.initials: V
authors.lastname: Manojkumar
authors.forename: P A
authors.initials: PA
authors.lastname: Kurup
mesh_terms: D000328:Adult; D015306:Biogenic Monoamines / Q000097:blood; D001927:Brain Diseases / Q000097:blood*; D001932:Brain Neoplasms / Q000097:blood; D004077:Digoxin / Q000032:analysis; D004829:Epilepsy, Generalized / Q000097:blood; D004912:Erythrocytes / Q000737:chemistry / Q000201:enzymology; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005910:Glioma / Q000097:blood; D018684:Glycine Agents / Q000097:blood; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000097:blood; D007736:Kynurenic Acid / Q000097:blood; D008274:Magnesium / Q000032:analysis; D008297:Male; D017566:Microvascular Angina / Q000097:blood; D008875:Middle Aged; D009020:Morphine / Q000097:blood; D009294:Narcotics / Q000097:blood; D009538:Nicotine / Q000097:blood; D018722:Nicotinic Agonists / Q000097:blood; D010300:Parkinson Disease / Q000097:blood; D017378:Quinolinic Acid / Q000097:blood; D012559:Schizophrenia / Q000097:blood*; D012709:Serum Albumin; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis; D013331:Strychnine / Q000097:blood; D014364:Tryptophan / Q000097:blood*; D014443:Tyrosine / Q000097:blood*; D014451:Ubiquinone / Q000032:analysis
chemical_list: D015306:Biogenic Monoamines; D005230:Fatty Acids, Nonesterified; D018684:Glycine Agents; D009294:Narcotics; D018722:Nicotinic Agonists; D012709:Serum Albumin; D014451:Ubiquinone; D014443:Tyrosine; D009538:Nicotine; D004077:Digoxin; D009020:Morphine; D014364:Tryptophan; D006903:Hydroxymethylglutaryl CoA Reductases; D000254:Sodium-Potassium-Exchanging ATPase; D017378:Quinolinic Acid; D007736:Kynurenic Acid; D013331:Strychnine; D008274:Magnesium