Fukuwatari Tsutomu, Wada Hideko, Shibata Katsumi
Department of Food Science and Nutrition, School of Human Cultures, The University of Shiga Prefecture, Hikone, Shiga, Japan.
J Nutr Sci Vitaminol (Tokyo). 2008 Oct;54(5):357-62. doi: 10.3177/jnsv.54.357.
To investigate how aging alters B-group vitamin metabolism, rats were fed with niacin-free 20% casein diet from 3 to 80 wk old, and the urinary excretions of the B group vitamins were periodically measured. The blood and liver B-group vitamin levels in 80-wk-old rats were also compared with those in 8-wk-old rats. The urinary excretion of thiamin, riboflavin, vitamin B6 metabolite 4-pyridoxic acid, pantothenic acid, folic acid and biotin were not altered during 540 d. The urinary vitamin B12 increased by 8-fold at 29 wk old, and further increased at 80 wk old. Conversion of nicotinamide from tryptophan gradually decreased to 60% from 29 to 48 wk old. Plasma PLP, vitamin B12 and folate levels in 80-wk-old rats were lower than those in 8-wk-old rats, consistent with lower liver vitamin B6 and folate levels in aged rats. Plasma and liver biotin levels in aged rats were higher than those in young rats. Other B-group vitamins such as vitamin B1, vitamin B2, niacin and pantothenic acid levels in blood and liver from aged rats were same as those from young rats. Alteration of vitamin B6 metabolism in particular is similar to the observations in elderly humans reported previously. Our findings suggest that aged rats can be useful models to investigate aging-related B-group vitamin metabolism.
为研究衰老如何改变B族维生素代谢，给大鼠从3周龄喂养至80周龄无烟酸的20%酪蛋白饮食，并定期测量B族维生素的尿排泄量。还将80周龄大鼠的血液和肝脏B族维生素水平与8周龄大鼠进行了比较。硫胺素、核黄素、维生素B6代谢物4-吡哆酸、泛酸、叶酸和生物素的尿排泄量在540天内未发生改变。尿维生素B12在29周龄时增加了8倍，并在80周龄时进一步增加。从29周龄到48周龄，色氨酸向烟酰胺的转化率逐渐降至60%。80周龄大鼠的血浆PLP、维生素B12和叶酸水平低于8周龄大鼠，这与老年大鼠肝脏中维生素B6和叶酸水平较低一致。老年大鼠的血浆和肝脏生物素水平高于年轻大鼠。老年大鼠血液和肝脏中的其他B族维生素，如维生素B1、维生素B2、烟酸和泛酸水平与年轻大鼠相同。特别是维生素B6代谢的改变与先前报道的老年人类的观察结果相似。我们的研究结果表明，老年大鼠可作为研究衰老相关B族维生素代谢的有用模型。
