May S. Reynolds

Use of ion-exchange resins for the determination of N1-methylnicotinamide in human urine.

Abstract A modification of the method of Huff and Perlzweig has been developed which is suitable for the fluorometric determination of N 1 -methylnicotinamide in human urine containing as little as 0.5 μmoles in a 24-hr collection. Approximately 50% of the fluorescence of untreated urine was removed by chromatography while recoveries of added synthetic N 1 -methylnicotinamide were essentially quantitative. The N 1 -methylnicotinamide values derived with the revised method were lower and more reproducible than those obtained when charcoal was used to remove interfering substances.

Interrelationships of methionine and vitamin B6 in human subjects.

Summary 1. A study of the interrelationship of methionine and pyridoxine was made in adult human subjects maintained on a semi-synthetic diet low in vit. B6. 2. No effect of a high dosage of methionine on the urinary excretion of B6 and its metabolites was observed in the study. 3. The role of vit. B6 in the methylation of nicotinamide is shown by the increased urinary excretion of N1-methylnicotinamide by human subjects, when given methionine plus pyridoxine but not when given only methionine.