Barford P A, Blair J A, Malghani M A
Br J Cancer. 1980 May;41(5):816-20. doi: 10.1038/bjc.1980.146.
The metabolism of 2-[14C]-folic acid, 2-[14C]-5-methyltetrahydrofolate 5-[14C]-methyltetrahydrofolate, and a mixture of 2-[14C]-folic acid and 3',5',7,9-[3H]-folic acid has been studied in rats that were dosed with methotrexate (MTX) 24 h before receiving the radioactive folate. Methotrexate increases urinary excretion of radioactivity in rats given 2-[14C]-folic acid, but there was no significant increase in urinary radioactivity in animals given 5-methyltetrahydrofolate. Animals dosed with MTX had less of the dose in the liver, and excreted more of the dose via the faeces. These results are consistent with the known biochemical effects of methotrexate. Experiments with a mixture of 2-[14C]-folic acid and 3',5',7,9-[3H]-folic acid indicate that there is an increase in scission of the folate molecule following a dose of MTX.
在给大鼠注射放射性叶酸前24小时给予甲氨蝶呤(MTX)的情况下,研究了2-[¹⁴C]-叶酸、2-[¹⁴C]-5-甲基四氢叶酸、5-[¹⁴C]-甲基四氢叶酸以及2-[¹⁴C]-叶酸与3',5',7,9-[³H]-叶酸混合物的代谢情况。甲氨蝶呤增加了给予2-[¹⁴C]-叶酸的大鼠尿液中放射性物质的排泄,但给予5-甲基四氢叶酸的动物尿液中放射性没有显著增加。给予MTX的动物肝脏中的剂量减少,且通过粪便排泄的剂量更多。这些结果与甲氨蝶呤已知的生化作用一致。用2-[¹⁴C]-叶酸和3',5',7,9-[³H]-叶酸混合物进行的实验表明,给予MTX后叶酸分子的裂解增加。