Masini-Repiso A M, Cabanillas A M, Bonaterra M, Coleoni A H
Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacionale de Córdoba, Argentina.
J Clin Endocrinol Metab. 1994 Jul;79(1):39-44. doi: 10.1210/jcem.79.1.8027249.
Several biochemical and functional modifications demonstrated in goitrous tissues could reflect the effect of goitrogenic factors. Growth-enhancing agents, including TSH itself, have been involved in goitrogenesis. To study comparatively the variation patterns of some TSH-dependent enzymes within single goitrous tissues, we measured the activities of peroxidase (TPO), NADPH-cytochrome-c (cyt-c) reductase, and monoamine oxidase (MAO) in tissues from cold follicular adenoma and multinodular goiter. Iodide transport and organification were also evaluated. Perinodular and necropsy tissues were used as controls. The mean TPO activity measured by guaiacol as well as triiodide assays was significantly increased in multinodular goiter, whereas a nonsignificant increment was observed in cold adenoma. NADPH-cyt-c reductase and MAO were markedly increased in the two types of pathological tissues. The individual activities of the three enzymes showed dissimilar modifications within single samples and among different tissues. There was no correlation in the activities of the enzymes within single specimens from cold adenoma and multinodular goiter, except for MAO and NADPH-cyt-c reductase in multinodular goiter, for which a significant correlation was obtained. In this tissue, MAO and TPO measured by guaiacol assay were weakly correlated. TPO activity evaluated by guaiacol oxidation was correlated with that measured by triiodide formation in cold adenoma, but not in multinodular goiter. The mean iodide organification values assayed by iodotyrosine formation in the absence of exogenous H2O2 in particulate fractions from cold adenoma and multinodular goiter were within the normal range. A reduced iodide transport, evaluated as the thyroid/medium ratio, was observed in slices from these tissues. The dissociation of the three enzyme activities in single specimens from cold adenoma and multinodular goiter along with the reduced iodide transport in these tissues support the hypothesis that factors other than TSH or with TSH-like effects could be involved in the abnormal thyroid growth.
甲状腺肿组织中表现出的几种生化和功能改变可能反映了致甲状腺肿因素的作用。包括促甲状腺激素（TSH）本身在内的生长促进剂与甲状腺肿的发生有关。为了比较研究单个甲状腺肿组织中一些TSH依赖性酶的变化模式，我们测量了冷滤泡性腺瘤和多结节性甲状腺肿组织中过氧化物酶（TPO）、NADPH-细胞色素c（cyt-c）还原酶和单胺氧化酶（MAO）的活性。还评估了碘转运和有机化情况。将结节周围组织和尸检组织用作对照。通过愈创木酚以及三碘化物测定法测得的多结节性甲状腺肿中TPO平均活性显著升高，而在冷腺瘤中观察到的升高不显著。NADPH-cyt-c还原酶和MAO在这两种病理组织中均显著升高。这三种酶的个体活性在单个样本内以及不同组织之间表现出不同的改变。冷腺瘤和多结节性甲状腺肿单个标本中酶的活性之间没有相关性，除了多结节性甲状腺肿中的MAO和NADPH-cyt-c还原酶，二者存在显著相关性。在该组织中，通过愈创木酚测定法测得的MAO和TPO呈弱相关。通过愈创木酚氧化评估的冷腺瘤中TPO活性与通过三碘化物形成测定的活性相关，但在多结节性甲状腺肿中不相关。在冷腺瘤和多结节性甲状腺肿的微粒体部分中，在无外源性H2O2的情况下通过碘酪氨酸形成测定的碘有机化平均值得出在正常范围内。以甲状腺/培养基比率评估，在这些组织的切片中观察到碘转运减少。冷腺瘤和多结节性甲状腺肿单个标本中三种酶活性的解离以及这些组织中碘转运的减少支持了这样的假说，即除TSH或具有TSH样作用的因素外，其他因素可能参与了甲状腺的异常生长。
