Metabolism of thiabendazole and teratogenic potential of its metabolites in pregnant mice.
作者:TOSHIE TSUCHIYA、AKIRA TANAKA、MASAMICHI FUKUOKA、MICHIO SATO、TSUTOMU YAMAHA
DOI:10.1248/cpb.35.2985
日期:——
In connection with the teratogenic activity of thiabendazole (TBZ), the metabolic fate of 14C-TBZ in pregnant mice was studied by administration of the drug in olive oil and gum arabic as vehicles. Absorption of TBZ in the olive oil group occurred more rapidly than in the gum arabic group, and the maximum blood level in the former group was 7-fold higher than that in the latter group. 5-Hydroxylated TBZ (5-HY TBZ), its glucuronide and its sulfate were identified as urinary and fecal metabolites. A very small quantity of N-methyl TBZ was also identified for the first time in the urine and feces. The percentages of TBZ, 5-HY TBZ, and the glucuronide and sulfate of 5-HY TBZ in the urine were 12-15, 22-24, 28-29 and 30-31%, respectively. About 97% of the dose was excreted into the urine (60-62%) and the feces (34-37%) within 7 d in each group. In a limb bud cell culture system for the assay of teratogenic potential, the concentrations of TBZ, 5-HY TBZ and N-methyl TBZ necessary to reduce the amounts of cartilage proteoglycan by 50% were estimated to be about 0.09, 0.09 and 0.24 mM, respectively. However, the concentrations of 5-HY TBZ glucuronide and sulfate were over 2 mM. Consequently, teratogenesis caused by TBZ appeared to be induced by the high levels of direct-acting teratogens such as TBZ and 5-HY TBZ when olive oil was used as a vehicle.
关于噻苯咪唑(TBZ)的致畸活性,我们以橄榄油和阿拉伯树胶为载体,研究了 14C-TBZ 在怀孕小鼠体内的代谢转归。橄榄油组对 TBZ 的吸收比阿拉伯树胶组更快,前者的最大血药浓度是后者的 7 倍。在尿液和粪便中发现了 5-羟基 TBZ(5-HY TBZ)、其葡萄糖醛酸苷和硫酸盐代谢物。在尿液和粪便中还首次发现了极少量的 N-甲基 TBZ。尿液中 TBZ、5-HY TBZ 以及 5-HY TBZ 的葡萄糖醛酸苷和硫酸盐的比例分别为 12-15%、22-24%、28-29% 和 30-31%。各组在 7 天内约有 97% 的剂量通过尿液(60-62%)和粪便(34-37%)排出体外。在用于检测致畸潜力的肢芽细胞培养系统中,将软骨蛋白多糖的数量减少 50%所需的 TBZ、5-HY TBZ 和 N-methyl TBZ 浓度估计分别约为 0.09、0.09 和 0.24 mM。但 5-HY TBZ 葡萄糖醛酸苷和硫酸盐的浓度超过 2 毫摩尔。因此,在使用橄榄油作为载体时,TBZ 导致的畸胎似乎是由高浓度的直接致畸剂(如 TBZ 和 5-HY TBZ)诱发的。