Haurani F I, Kauh Y S, Abboud E M
Mol Cell Biochem. 1985 Jan;65(2):153-7. doi: 10.1007/BF00221098.
In this study, cobalamin deficiency was produced in vitro by the use of nitrous oxide, known to inactivate the vitamin. In 14 sets of experiments, normal human lymphocytes stimulated with phytohemagglutinin on day 0 were exposed to nitrous oxide and oxygen on day 2. MeCbl was delivered later to half of the cells. Untreated cells served as a control. On day 3, the cells were harvested, the lymphocytes were lysed, and the obtained extracts were assayed for thymidylate synthetase. In 16 other experiments the same procedure was performed, and the incorporation of radioactive thymidine or deoxyuridine by the intact cells was measured. In additional experiments, a deoxyuridine suppression test of treated and untreated stimulated lymphocytes was also performed. The results indicate that nitrous oxide significantly reduces the activity of thymidylate synthetase and that this reduction is significantly corrected by MeCbl, suggesting a causative relation between the vitamin and the enzyme. However, there was no statistically significant effect of nitrous oxide demonstrated on the nucleoside incorporation nor on the deoxyuridine suppression test.
在本研究中，通过使用已知会使维生素失活的一氧化二氮在体外造成钴胺素缺乏。在14组实验中，于第0天用植物血凝素刺激的正常人淋巴细胞在第2天暴露于一氧化二氮和氧气中。随后向一半细胞中递送甲钴胺。未处理的细胞用作对照。在第3天，收获细胞，裂解淋巴细胞，并对获得的提取物进行胸苷酸合成酶测定。在另外16组实验中，进行相同的操作，并测量完整细胞对放射性胸苷或脱氧尿苷的掺入情况。在额外的实验中，还对处理过和未处理的受刺激淋巴细胞进行了脱氧尿苷抑制试验。结果表明，一氧化二氮显著降低胸苷酸合成酶的活性，并且这种降低可被甲钴胺显著纠正这表明该维生素与该酶之间存在因果关系。然而，未证明一氧化二氮对核苷掺入或脱氧尿苷抑制试验有统计学上的显著影响。
