Lindsay R H, Kelly K, Hill J B
Endocrinology. 1979 Jun;104(6):1686-97. doi: 10.1210/endo-104-6-1686.
The identities and relative amounts of the major metabolites in rat thyroids 6 h after the administration of [14C]propylthiouracil ([14C]PTU) have been investigated. Rat thyroid extracts were chromatographed on columns of Bio-Gel P-2 and DEAE-Sephadex and in various thin layer chromatography systems. The extracts contained protein-bound PTU metabolites; an unknown peak 3; peak 1, which was chromatographically similar to PTU--SO2H; peak 2, which was similar to PTU--SO3H; PTU; and small amounts of 6-n-propyluracil (PU). The major metabolites were isolated and purified by column chromatograpy. On the basis of chromatographic properties identical to cochromatographed standards in seven different systems and the products formed after treatment with various reagents, peak 1 was identified as PTU-SO2H and peak 2 as PTU--SO3H. Peak 3 was seen only on Bio-Gel P-2 columns, was very unstable, and was not similar to any known PTU standard. The properties of this compound suggest that it may be a thiolsulfonic ester (formula:see text), but the data are insufficient for positive identification. Approximately 85% of the radioactivity in the protein peak was bound to thyroglobulin. HCl converted 86.5% of the protein-bound radioactivity to PU, and H2S converted 91% to PTU, indicating that an oxidized S was involved in the linkage to protein. Dithiothreitol released 23.6% of the protein-bound radioactivity as PTU, and mercaptoethanol released 32.5%, indicating that 25-35% of the PTU is bound in disulfide linkage. Approximately 50% of the radioactivity released by mercaptoethanol was S-ethanol PTU, which suggests a PTU-protein bond similar to a thiolsulfonic ester. Quantitation of the metabolites revealed that protein-bound metabolites accounted for 21-29% of the total radioactivity, unknown peak 3 accounted for 7.1%, PTU--SO2H for 48-50%, PTU--SO3H for 8-10%, and PTU for 10.7-16.5%. Only traces of PU were observed. The data demonstrate that PTU--SO2H is the major PTU metabolite in rat thyroid and must be the compound X observed by other investigators and that all metabolites identified are oxidative products of PTU. These findings support the earlier conclusion of Taurog and Riesco that protein binding of PTU occurs as a consequence of oxidation.
在给予[14C]丙硫氧嘧啶（[14C]PTU）6小时后，对大鼠甲状腺中主要代谢产物的种类和相对含量进行了研究。大鼠甲状腺提取物在Bio - Gel P - 2和DEAE - Sephadex柱上以及各种薄层色谱系统中进行色谱分析。提取物中含有与蛋白质结合的PTU代谢产物；未知峰3；峰1，其色谱行为与PTU - SO2H相似；峰2，与PTU - SO3H相似；PTU；以及少量的6 - 正丙基尿嘧啶（PU）。主要代谢产物通过柱色谱法进行分离和纯化。基于在七种不同系统中与共色谱标准品相同的色谱性质以及用各种试剂处理后形成的产物，峰1被鉴定为PTU - SO2H，峰2为PTU - SO3H。峰3仅在Bio - Gel P - 2柱上出现，非常不稳定，且与任何已知的PTU标准品都不相似。该化合物的性质表明它可能是一种硫代磺酸酯（分子式：见正文），但数据不足以进行明确鉴定。蛋白质峰中约85%的放射性与甲状腺球蛋白结合。HCl将86.5%与蛋白质结合的放射性转化为PU，H2S将91%转化为PTU，表明氧化态的S参与了与蛋白质的连接。二硫苏糖醇释放出23.6%与蛋白质结合的放射性作为PTU，巯基乙醇释放出32.5%，表明25 - 35%的PTU以二硫键结合。巯基乙醇释放的放射性中约50%是S - 乙醇PTU，这表明PTU与蛋白质的键类似于硫代磺酸酯。代谢产物的定量分析表明，与蛋白质结合的代谢产物占总放射性的21 - 29%，未知峰3占7.1%，PTU - SO2H占48 - 50%，PTU - SO3H占8 - 10%，PTU占10.7 - 16.5%。仅观察到痕量的PU。数据表明PTU - SO2H是大鼠甲状腺中主要的PTU代谢产物，必定是其他研究者观察到的化合物X，并且鉴定出的所有代谢产物都是PTU的氧化产物。这些发现支持了Taurog和Riesco早期的结论，即PTU与蛋白质的结合是氧化的结果。
