Nishida M, Muraoka K, Nishikawa K, Takagi T, Kawada J
Faculty of Pharmaceutical Sciences, University of Tokushima, Japan.
J Histochem Cytochem. 1989 May;37(5):723-7. doi: 10.1177/37.5.2703707.
This study was designed to characterize the interaction of CH3HgCl or HgCl2 with thyroid peroxidase (TPO). Two types of experiments were performed. First, the thyroids from rats that were given 5.6 mg/kg/day of either CH3HgCl or HgCl2 for 2 weeks by intubation were subjected to histochemical treatment and then to electron microscopy. TPO activities in all cell compartments were inhibited by HgCl2 but not by CH3HgCl. Morphological observation showed that taller epithelia were induced by HgCl2, whereas flattened epithelia forming large follicles were induced by CH3HgCl. The serum thyrotropin level was substantially lowered by CH3HgCl but was unchanged by HgCl2. Second, the guaiacol oxidation by TPO in isolated and ruptured pig thyroid cells was spectrophotometrically monitored in the presence of either CH3HgCl or HgCl2. The TPO was not inhibited by CH3HgCl but was inhibited by HgCl2. These results indicated that CH3HgCl induced a hypothyroid state without affecting TPO, whereas HgCl2 inhibited TPO and induced a hypertropic state owing to compensation for loss of enzyme activity, and that the lack of inhibitory activity of CH3HgCl was not due to the inability to penetrate the cells. Therefore, there appeared to be a differential interaction of organic and inorganic forms of mercurials with the thyroid.
本研究旨在表征氯化甲基汞（CH3HgCl）或氯化汞（HgCl2）与甲状腺过氧化物酶（TPO）的相互作用。进行了两类实验。首先，对通过插管给予5.6 mg/kg/天的CH3HgCl或HgCl2持续2周的大鼠甲状腺进行组织化学处理，然后进行电子显微镜观察。HgCl2抑制了所有细胞区室中的TPO活性，但CH3HgCl未产生抑制作用。形态学观察表明，HgCl2诱导上皮细胞变高，而CH3HgCl诱导形成大滤泡的扁平上皮细胞。CH3HgCl使血清促甲状腺激素水平大幅降低，但HgCl2未使其发生变化。其次，在存在CH3HgCl或HgCl2的情况下，用分光光度法监测分离并破裂的猪甲状腺细胞中TPO对愈创木酚的氧化作用。CH3HgCl未抑制TPO，但HgCl2抑制了TPO。这些结果表明，CH3HgCl在不影响TPO的情况下诱导甲状腺功能减退状态，而HgCl2抑制TPO并由于对酶活性丧失的代偿而诱导甲状腺增生状态，并且CH3HgCl缺乏抑制活性并非由于其无法穿透细胞。因此，汞的有机和无机形式与甲状腺之间似乎存在差异相互作用。
