Samuels L L, Feinberg A, Moccio D M, Sirotnak F M, Rosen G
Biochem Pharmacol. 1984 Sep 1;33(17):2711-4. doi: 10.1016/0006-2952(84)90685-3.
Methotrexate (MTX) polyglutamates were detected in osteogenic sarcoma tumor samples obtained from patients 24 or 48 h after receiving high-dose MTX/leucovorin rescue therapy. Tumor samples were assayed by high-performance liquid chromatography, and polyglutamyl metabolites, along with MTX, were quantitated using both direct u.v. absorption at 313 nm and an enzyme titration assay. Good agreement between these two methods was found although the more sensitive enzyme assay detected peaks in some samples not detected by u.v. absorbance. A wide variation in MTX:MTX polyglutamate levels (1:1 to 25:1) was found among the six clinical samples studied. Also, no correlation between the extent of polyglutamate formation and plasma levels (determined at the time of tumor sampling) was observed. High intracellular levels of a derivative which appears to be the 7-hydroxy metabolite of MTX were also detected in four of six samples. This material coeluted with authentic standard, showed spectral properties like standard 7-OH-MTX, and did not inhibit dihydrofolate reductase.
在接受高剂量甲氨蝶呤/亚叶酸钙解救治疗24或48小时后从患者获取的骨肉瘤肿瘤样本中检测到甲氨蝶呤（MTX）多聚谷氨酸盐。肿瘤样本通过高效液相色谱法进行分析，多聚谷氨酰代谢产物以及MTX通过313nm处的直接紫外吸收和酶滴定法进行定量。尽管更灵敏的酶法检测到了一些紫外吸光法未检测到的样本中的峰，但发现这两种方法之间有很好的一致性。在所研究的六个临床样本中发现MTX：MTX多聚谷氨酸盐水平存在很大差异（1:1至25:1）。此外，未观察到多聚谷氨酸盐形成程度与血浆水平（在肿瘤取样时测定）之间的相关性。在六个样本中的四个样本中还检测到一种衍生物的高细胞内水平，该衍生物似乎是MTX的7-羟基代谢产物。该物质与标准品共洗脱，显示出与标准7-OH-MTX相似的光谱特性，并且不抑制二氢叶酸还原酶。
