Vitamin effects on tryptophan-niacin metabolism in primary hepatoma patients.
Metabolism of 14C-labeled tryptophan and 3-hydroxyanthranilic acid were administered to early hepatoma patients to evaluate the conversion of these precursors to niacin metabolites and to assess the effect of dietary supplementation with vitamin B-6, riboflavin, thiamin and vitamin C on the extent of conversion. Expired labeled carbon dioxide and urinary excretion of picolinic acid (PA), quinolinic acid (QA), nicotinic acid (NA), N1-methylnicotinamide (N1MeNAm) and N1-methyl-2-pyridone-5-carboxamide (MPCA) were measured by carrier isolations. There were no consistent statistical differences in these conversions before and after vitamin supplementation, suggesting that the patients' nutrition was adequate and that none of the vitamins were rate-limiting under these conditions.
Hankes
L V
LV
Biochemistry Div., Brookhaven National Laboratory, Upton New York 11973, USA.
Schmaeler
M
M
Jansen
C R
CR
Brown
R R
RR
D015095:3-Hydroxyanthranilic Acid / Q000378:metabolism; D001711:Biotransformation; D044383:Black People; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D019587:Dietary Supplements; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism*; D008297:Male; D009525:Niacin / Q000378:metabolism*; D009747:Nutritional Physiological Phenomena; D011736:Pyridoxine / Q000494:pharmacology / Q000627:therapeutic use; D012256:Riboflavin / Q000494:pharmacology / Q000627:therapeutic use; D013019:South Africa; D013831:Thiamine / Q000494:pharmacology / Q000627:therapeutic use; D014364:Tryptophan / Q000378:metabolism*; D014815:Vitamins / Q000494:pharmacology*
D002250:Carbon Radioisotopes; D014815:Vitamins; D015095:3-Hydroxyanthranilic Acid; D009525:Niacin; D014364:Tryptophan; D011736:Pyridoxine; D012256:Riboflavin; D013831:Thiamine