抄録
After intraperitoneal injection of riboflavin tetranicotinate (B_2-NiA) equivalent to 150 mg/kg of nicotinic acid, the amount of NAD in the mouse liver attained the maximum value at 8 hours, which was considerably higher than in the case of nicotinic acid and almost the same as that in the case of nicotinamide 150mg/kg. Larger dose of B_2-NiA caused to delay the time to the maximum amount of NAD, but the amount was rather small. However, the amount of NAD in the liver 8 hours after oral administration increased as the dose of B_2-NiA increased. The amount was more than in the case of nicotinic acid, but much less than nicotinamide. The total amount of riboflavin in the liver exhibited transient increase after intraperitoneal injection of B_2-NiA. That was attributed to increase of free riboflavin, B_2-NiA and its partial hydrolysates, and the amounts of FAD and FMN were constantly kept in the same as the normal values. In the case of oral administration of B_2-NiA, the total amount of riboflavin in the liver was not changed, and B_2-NiA and its partial hydrolysates were not demonstrated in the liver, though they were found in the large amounts in the intestinal contents.
