Abstract
Women students were administered three times 50 mg of nicotinamide after meal, the 24-hour urine was collected and the urinary excretions of N^1-methylnicotinamide (MNA), N^1-methyl-2-pyridone-5-carboxamide (2-Pyr) and N^1-methyl-4-pyridone-3-carboxamide (4-Pyr) were measured. Furthermore, 10 μl of blood was taken from finger 2 hour after the lunch and the blood NAD and NADP values were measured. As the results, the urinary excretions of MNA, 2-Pyr and 4-Pyr was increased 8, 13- and 13-folds, respectively, compared with those of the control period. A recommended index of niacin nutrition, (2-Pyr+4-Pyr)/MNA excretion was increased by 1.7-fold by nicotinamide load. The blood NAD level was 1.7-fold higher in the loading period than in the control period, but the blood NADP level was almost the same between the two period. From these results, it was found that blood NAD level as well as (2-Pyr+4-Pyr)/MNA excretion would be used as an index of niacin nutrition in humans.
