Nielsen F H, Uthus E O, Poellot R A, Shuler T R
United States Department of Agriculture, Agricultural Research Service, Grand Forks Human Nutrition Research Center, ND 58202.
Biol Trace Elem Res. 1993 Apr;37(1):1-15. doi: 10.1007/BF02789397.
An experiment was performed to ascertain whether changing the dietary intake of two substances, cystine and margaric acid (heptadecanoic acid), that affect the flux through pathways involving the two vitamin B12-dependent enzymes, methionine synthase and methylmalonyl-CoA mutase, would affect the interaction between nickel and vitamin B12. Rats were assigned to treatment groups of six in a fully crossed, four-factorial arrangement. The independent variables, or factors, were: per kg of fresh diet, nickel analyzed at 25 and 850 micrograms; vitamin B12 supplements of 0 and 50 micrograms; margaric acid supplements of 0 and 5 g; and L-cystine supplements of 0 and 12 g. The diet without cystine was marginally deficient in sulfur amino acids. Nickel affected growth, liver wt/body wt ratio (LB/BW), and a number of variables associated with iron, calcium, zinc, copper, and magnesium metabolism. Most of the effects of nickel were modified by the vitamin B12 status of the rat. In numerous cases, the interaction between nickel and vitamin B12 was dependent on, or altered by, the cystine or margaric acid content of the diet. Thus, the findings showed that the extent and the direction of changes in numerous variables in response to nickel deprivation varied greatly with changes in diet composition. These variables include those previously reported to be affected by nickel deprivation, including growth and the distribution or functioning of iron, calcium, zinc, copper, and magnesium. The findings also support the hypothesis that nickel has a biological function in a metabolic pathway in which vitamin B12 is important.
进行了一项实验，以确定改变两种物质（胱氨酸和十七烷酸）的饮食摄入量是否会影响镍与维生素B12之间的相互作用。这两种物质会影响涉及两种维生素B12依赖性酶（甲硫氨酸合酶和甲基丙二酰辅酶A变位酶）的代谢途径通量。大鼠被分配到六个处理组，采用完全交叉的四因素设计。自变量或因素包括：每千克新鲜饮食中，镍含量分别为25微克和850微克；维生素B12补充量分别为0微克和50微克；十七烷酸补充量分别为0克和5克；L-胱氨酸补充量分别为0克和12克。不含胱氨酸的饮食在硫氨基酸方面略有不足。镍影响生长、肝脏重量/体重比（LB/BW）以及许多与铁、钙、锌、铜和镁代谢相关的变量。镍的大多数影响因大鼠的维生素B12状态而改变。在许多情况下，镍与维生素B12之间的相互作用取决于饮食中的胱氨酸或十七烷酸含量，或因它们而改变。因此，研究结果表明，因镍缺乏而导致的众多变量变化的程度和方向会因饮食组成的变化而有很大差异。这些变量包括先前报道的受镍缺乏影响的变量，包括生长以及铁、钙、锌、铜和镁的分布或功能。研究结果还支持了镍在维生素B12起重要作用的代谢途径中具有生物学功能这一假设。
