Yamauchi H, Yamamura Y
Toxicology. 1985 Feb;34(2):113-21. doi: 10.1016/0300-483x(85)90161-1.
It was shown that a single dose of arsenic trioxide administered to hamsters was chiefly methylated in vivo into methylarsonic acid (MAA) and dimethylarsinic acid (DMAA), and that inorganic arsenic accounted for the major portion of total arsenic that deposited in organs and tissues, followed by MAA and DMAA in decreasing sequence of significance. The single oral dose of arsenic trioxide was followed by a very small amount of trimethylarsenic compounds (TMA) occurring only in the liver but not in any other organs, tissues, blood or feces. The distribution pattern of arsenic in the blood following the single oral dose of arsenic trioxide was such that inorganic arsenic and MAA occurred chiefly in the blood cells; DMAA, chiefly in the plasma; and the arsenic compounds disappeared rapidly from blood. The single oral dose of arsenic trioxide was further followed by excretion of an amount of arsenic equivalent to about 60% of the administered dose: 49% in the urine and 11% in the feces. In other words, more arsenic tended to be excreted in the urine. DMAA accounted for the major portion of arsenic excreted in the urine and feces, and this finding re-confirmed that DMAA is the major metabolite of arsenic trioxide. Although it is believed that arsenic trioxide is not converted into TMA, the results of the present study suggest that a very small amount of arsenic trioxide is converted into TMA in the liver.
结果表明，给仓鼠单次服用三氧化二砷后，其在体内主要甲基化生成甲基胂酸（MAA）和二甲基胂酸（DMAA），沉积于器官和组织中的总砷主要以无机砷为主，其次是MAA和DMAA，其重要性依次递减。单次口服三氧化二砷后，仅在肝脏中出现极少量的三甲基砷化合物（TMA），其他器官、组织、血液或粪便中均未出现。单次口服三氧化二砷后，血液中砷的分布模式如下：无机砷和MAA主要存在于血细胞中；DMAA主要存在于血浆中；砷化合物迅速从血液中消失。单次口服三氧化二砷后，随后排出的砷量约相当于给药剂量的60%：49%通过尿液排出，11%通过粪便排出。换句话说，则更多的砷倾向于通过尿液排出。DMAA占尿液和粪便中排出砷的大部分，这一发现再次证实DMAA是三氧化二砷的主要代谢产物。虽然人们认为三氧化二砷不会转化为TMA，但本研究结果表明，极少量的三氧化二砷在肝脏中会转化为TMA。
