Schaeffer M C, Sampson D A, Skala J H, Gietzen D W, Grier R E
Western Human Nutrition Research Center, U.S. Department of Agriculture/Agricultural Research Service, San Francisco, CA 94129.
J Nutr. 1989 Oct;119(10):1392-8. doi: 10.1093/jn/119.10.1392.
We compared the vitamin B-6 status of 12-wk-old rats (n = 12) fed excess (1400 mg/kg diet) or the recommended level (7 mg/kg diet, control) of pyridoxine (PN) hydrochloride to test if excess vitamin B-6 would cause tissue depletion of pyridoxal phosphate (PLP), the active coenzyme form of vitamin B-6. Plasma PLP, tryptophan-load test results, food intake, and tissue and body weights were not different at wk 6. Red blood cell endogenous alanine aminotransferase activity and PLP concentration were elevated (P less than 0.01) in rats fed 1400 mg PN.HCl/kg diet. In contrast, PLP concentration in muscle was significantly lower (P = 0.01) in rats fed excess vitamin B-6 (9.7 +/- 0.8 nmol/g, mean +/- SEM) than in controls (14.9 +/- 1.4). PLP concentration in other tissues, including plasma, was not affected. In rats fed excess vitamin B-6, pyridoxal was increased in all tissues examined (P less than 0.05), and total vitamin B-6 was increased in plasma, red blood cells and kidneys (P less than 0.05). Total glycogen phosphorylase (a + b) activity in the gastrocnemius was not affected, but phosphorylase a activity was increased in rats fed excess vitamin B-6 (P = 0.025). Concentrations of dopamine and metabolites in the caudate nucleus of the basal ganglia were not affected. A transient, but significant, elevation in acoustic startle response, a central nervous system reflex, was observed in rats fed excess vitamin B-6. The depletion in muscle PLP could not hae been predicted by either plasma or red blood cell PLP concentration, although the latter did reflect vitamin B-6 intake.(ABSTRACT TRUNCATED AT 250 WORDS)
我们比较了12周龄大鼠（n = 12）的维生素B-6状态，这些大鼠分别喂食过量（1400毫克/千克饮食）或推荐水平（7毫克/千克饮食，对照）的盐酸吡哆醇（PN），以测试过量的维生素B-6是否会导致磷酸吡哆醛（PLP）的组织消耗，PLP是维生素B-6的活性辅酶形式。第6周时，血浆PLP、色氨酸负荷试验结果、食物摄入量以及组织和体重并无差异。喂食1400毫克PN.HCl/千克饮食的大鼠，其红细胞内源性丙氨酸转氨酶活性和PLP浓度升高（P小于0.01）。相比之下，喂食过量维生素B-6的大鼠肌肉中的PLP浓度（9.7±0.8纳摩尔/克，平均值±标准误）显著低于对照组（14.9±1.4）（P = 0.01）。包括血浆在内的其他组织中的PLP浓度未受影响。在喂食过量维生素B-6的大鼠中，所有检测组织中的吡哆醛均增加（P小于0.05），血浆、红细胞和肾脏中的总维生素B-6增加（P小于0.05）。腓肠肌中的总糖原磷酸化酶（a + b）活性未受影响，但喂食过量维生素B-6的大鼠中磷酸化酶a活性增加（P = 0.025）。基底神经节尾状核中的多巴胺及其代谢产物浓度未受影响。在喂食过量维生素B-6的大鼠中，观察到作为中枢神经系统反射的听觉惊吓反应出现短暂但显著的升高。尽管红细胞PLP浓度确实反映了维生素B-6的摄入量，但肌肉PLP的消耗无法通过血浆或红细胞PLP浓度来预测。（摘要截短于250字）
