Cox P J, Phillips B J, Thomas P
Cancer Res. 1975 Dec;35(12):3755-61.
The initial metabolic products of cyclophosphamide (4-hydroxy-cyclophosphamide and aldophosphamide) were prepared biologically in unpurified form. Their toxicity to tumor cells were tested by bioassay techniques and in cell culture, and the deactivation abilities of various tissue-soluble fractions were quantitated. Liver and kidney cytosol effectively deactivated the primary metabolites, whereas cytosols from gastrointestinal tract mucosa, Walker ascites tumor, and spleen were less efficient. When [14C]cyclophosphamide was activated and incubated with liver cytosol, 34% of all radioactivity was identified as carboxyphosphamide, by mass spectrometry of the methyl ester. Measurement of alcohol dehydrogenase (EC 1.1.1.1) and aldehyde dehydrogenase (EC 1.2.1.3) activities by reduced nicotinamide adenine dinucleotide production revealed a qualitative correspondence between aldehyde dehydrogenase activity and deactivation ability. Unpurified aldophosphamide and the analogs prepared from 6-methyl- and 5,5-dimethylcyclophosphamides were substrates for nicotinamide adenine dinucleotide-requiring enzymes, whereas incubation of 4-hydroxy-4-methylcyclophosphamide in an unfractionated incubation mixture with liver soluble enzymes did not cause reduced nicotinamide adenine dinucleotide production.
环磷酰胺的初始代谢产物（4-羟基环磷酰胺和醛磷酰胺）是以未纯化的形式通过生物学方法制备的。通过生物测定技术和细胞培养测试了它们对肿瘤细胞的毒性，并对各种组织可溶性组分的失活能力进行了定量。肝和肾胞质溶胶能有效使主要代谢产物失活，而胃肠道黏膜、沃克腹水瘤和脾脏的胞质溶胶效率较低。当[14C]环磷酰胺被激活并与肝胞质溶胶一起孵育时，通过甲酯的质谱分析，所有放射性的34%被鉴定为羧磷酰胺。通过还原型烟酰胺腺嘌呤二核苷酸的产生来测量乙醇脱氢酶（EC 1.1.1.1）和醛脱氢酶（EC 1.2.1.3）的活性，结果显示醛脱氢酶活性与失活能力之间存在定性对应关系。未纯化的醛磷酰胺以及由6-甲基环磷酰胺和5,5-二甲基环磷酰胺制备的类似物是需要烟酰胺腺嘌呤二核苷酸的酶的底物，而在未分级的孵育混合物中，将4-羟基-4-甲基环磷酰胺与肝可溶性酶一起孵育不会导致还原型烟酰胺腺嘌呤二核苷酸的产生。
