Peroxidase activity and thyroglobulin iodination activity of thyroid peroxidase in non-functioning thyroid tumours.
Both lesion (L) and adjacent normal (N) thyroid tissue from 48 patients with non-functioning adenomas and adenomatous goitres were assayed for peroxidase activity by the 'mini' assay method employing guaiacol or iodide as the second substrate. A considerable proportion of thyroids (46% of adenomas and 22% of adenomatous goitres) demonstrated no iodide oxidation activity in L although they had guaiacol oxidation activity, and these were grouped as subgroups A. The rest of these non-functioning tumours, termed subgroups B, had both guaiacol and iodide oxidation activity which was higher (3.0-4.6 times in guaiacol assay and 7.3-14.1 times in iodide assay) in L than in N. These data indicate that the non-functioning in subgroups A may be due to a lack of iodide oxidation activity and that some other defects such as an iodide transport defect may be involved in subgroups B. Furthermore, a precise and rapid assay method for thyroglobulin iodination activity of thyroid peroxidase was developed, with modifications of previous methods. On the basis of this method, we found that there is a good correlation (r = 0.94) between iodide oxidation assay and thyroglobulin iodination assay, leading to the conclusion that thyroglobulin iodination assay can be replaced by iodide oxidation assay.
Yoshimura
H
H
Faculty of Pharmaceutical Sciences, Chiba University, Japan.
Ito
K
K
Tarutani
O
O
Hosoya
T
T
D000236:Adenoma / Q000378:metabolism*; D005949:Glucose Oxidase / Q000378:metabolism; D006042:Goiter / Q000378:metabolism; D006139:Guaiacol / Q000378:metabolism; D006801:Humans; D007453:Iodide Peroxidase / Q000378:metabolism*; D007455:Iodine / Q000378:metabolism; D010084:Oxidation-Reduction; D013954:Thyroglobulin / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000378:metabolism*
D006139:Guaiacol; D013954:Thyroglobulin; D007455:Iodine; D005949:Glucose Oxidase; D007453:Iodide Peroxidase