Simultaneous micro-determination of nicotinamide and its major metabolites, N1-methyl-2-pyridone-5-carboxamide and N1-methyl-4-pyridone-3-carboxamide, by high-performance liquid chromatography

Urinary Excretory Ratio of Anthranilic Acid/Kynurenic Acid as an Index of the Tolerable Amount of Tryptophan

“…KA, xanthurenic acid (XA), 3-hydroxyanthranic acid (3-HA), and N 1 -methylnicotinamide chloride (MNA) were purchased from Tokyo Kasei Kogyo (Tokyo, Japan). N 1 -methyl-2-pyridone-5-carboxamide (2-Py) and N 1 -methyl-4-pyridone-3-carboxamide (4-Py) were synthesized by the methods of Pullman and Colowick 7) and Shibata et al, 8) respectively. The mineral (AIN-93-G-MX) and nicotinic acid-free vitamin (AIN-93-VX) mixtures were obtained from Oriental Yeast Kogyo (Tokyo, Japan).…”

Twenty-four-hour urinary water-soluble vitamin levels correlate with their intakes in free-living Japanese university students

“…To measure urinary vitamin B 12 , urine samples were added to 0.2 mmol/l acetate buffer (pH 4.8), vitamin B 12 was converted to cyanocobalamin by boiling with 0.0006% potassium cyanide at acidic pH, and cyanocobalamin was determined by a microbioassay using Lactobacillus leichmanii ATCC 7830 (Watanabe et al, 1999). Urinary N 1 -methyl-2-pyridone-5-carboxamide, N 1 -methyl-4-pyridone-3-carboxamide (Shibata et al, 1988), and N 1 -methylnicotinamide (Shibata, 1987) were determined by the HPLC method, and the sum of these compounds was determined as nicotinamide metabolites. Urinary pantothenic acid was determined by a microbioassay using Lactobacillus plantarum ATCC 8014 (Skeggs and Wright, 1944).…”

Effects of Fatty Liver Induced by Niacin-free Diet with Orotic Acid on the Metabolism of Tryptophan to Niacin in Rats

“…Kynurenine sulfate, kynurenic acid, 3-hydroxyanthranilic acid, and N 1 -methylnicotinamide chloride were purchased from Tokyo Kasei Kogyo (Tokyo, Japan). N 1 -methyl-2-pyridone-5-carboxamide and N 1 -methyl-4-pyridone-5-carboxamide were synthesized by the methods of Pullman and Colowick 22) and of Shibata et al, 23) respectively. Gelatinized cornstarch and corn oil were purchased from Nichiden Kagaku (Tokyo, Japan) and Ajinomoto (Tokyo, Japan), respectively.…”

“…The conversion ratio was calculated as the sum of the urinary excretions of nicotinamide+N 1 -methylnicotinamide+N 1 -methyl-2-pyridone-5-carboxamide+N 1 -methyl-4-pyridone-5-carboxamide (mmol W day)×100 W tryptophan intake during urine collection (mmol W day). The contents of nicotinamide, N 1 -methyl-2-pyridone-5-carboxamide, and N 1 -methyl-4-pyridone-5-carboxamide in the urine were simultaneously measured by the HPLC method of Shibata et al, 23) while the content of N 1 -methylnicotinamide in the urine was measured by the HPLC method of Shibata. 28) The contents of kynurenic acid, 29) xanthurenic acid, 30) anthranilic acid, 31) 3-hydroxyanthranilic acid, 30) and quinolinic acid 32) in the urine were measured by HPLC.…”