论文部分内容阅读
接触一氧化氮能选择性地干扰维生素B_(12)的辅酶功能,并引起蛋氨酸合成酶的失活,继而损害叶酸代谢,减少细胞增殖。在大鼠白血病模型(BNML)中,作者研究了一氧化氮、失活的维生素B_(12)、氨甲蝶吟(MTX)的联合用药,是抑制二氢叶酸还原酶的叶酸拮抗剂。通过不同的作用机制,两种药物均降低四氢叶酸盐的有效性,继之也降低了其它还原叶酸盐的有效性,并加重损害了依赖叶酸的胸苷酸合成。
Exposure to nitric oxide selectively disrupts the coenzyme function of vitamin B 12 and causes inactivation of methionine synthase, which in turn can impair folic acid metabolism and decrease cell proliferation. In the rat leukemia model (BNML), the authors studied the combination of nitric oxide, inactivated vitamin B 12, and methotrexate (MTX), a folate antagonist that inhibits dihydrofolate reductase. Both drugs reduce the effectiveness of the tetrahydrofolate by different mechanisms of action, followed by its effectiveness in reducing other reduced folate and aggravating the synthesis of thymidylate that is dependent on folate.