Shibata K, Onodera M, Taniguchi M, Taniguchi N
Department of Food Science and Nutrition, Osaka International University for Women, Japan.
Biochem Int. 1992 Mar;26(3):389-95.
Metabolic fates of nicotinamide in Wistar and LEC rats were compared. In Wistar rats (normal rats) nicotinamide was generally catabolized to N1-methyl-4-pyridone-3-carboxamide (4-Py) through N1-methylnicotinamide (MNA). But in LEC rats nicotinamide catabolism mainly stopped at MNA. Therefore, the excretion ratio of (N1-methyl-2-pyridone-5-carboxamide + 4-Py)/MNA, which is an index of amino acid adequacy, was much lower in the LEC rats than in the Wistar rats. This phenomenon was attributed to the fact that the 4-Py-forming MNA oxidase activity was much lower in the LEC rats than in the Wistar rats. The NAD contents in liver and blood were also lower in LEC rats than in Wistar rats. These results suggest that the ability to synthesize proteins such as 4-Py-forming MNA oxidase and dehydrogenases may be impaired in LEC rats.
比较了烟酰胺在Wistar大鼠和LEC大鼠体内的代谢命运。在Wistar大鼠（正常大鼠）中，烟酰胺通常通过N1-甲基烟酰胺（MNA）分解代谢为N1-甲基-4-吡啶酮-3-甲酰胺（4-Py）。但在LEC大鼠中，烟酰胺的分解代谢主要停留在MNA阶段。因此，作为氨基酸充足指标的（N1-甲基-2-吡啶酮-5-甲酰胺 + 4-Py）/MNA排泄率，LEC大鼠比Wistar大鼠低得多。这种现象归因于LEC大鼠中生成4-Py的MNA氧化酶活性比Wistar大鼠低得多。LEC大鼠肝脏和血液中的NAD含量也比Wistar大鼠低。这些结果表明，LEC大鼠合成诸如生成4-Py的MNA氧化酶和脱氢酶等蛋白质的能力可能受损。
