Effect of MMI on the serum T3 and T4 levels in hyperthyroid patients (author's transl)

Abstract

Effect of 1-methyl-2-mercaptoimidazole (MMI) on the serum triiodothyronine (T3) and thyroxine (T4) was studied in six patients with hyperthyroidism. From 30 to 60 mg of MMI per day were administered to the patients orally. Serum T3 was measured by radioimmunoassay and T4 by radioimmunoassay of Tetrasorb Kit (Abbott Lab.). Serum T4/T3 ratios in these patients were low initially, but increased to normal range in two cases immediately after the administration of MMI. But they were unchanged at first in the other four cases. When high serum T3 values decreased abruptly to normal at a later course of medication, the serum T4/T3 ratios increased to normal range in almost all cases. Even though the serum T4/T3 ratio became normal, serum T3 and T4 values remained high in some cases. Elevated serum T4 values in all cases decreased to normal faster than serum T3 with the administration of MMI. When MMI was administered to the patents concinuously, the T4/T3 ratios, once increased to normal, then decreased again gradually in five cases. And serum T3 which decreased to normal sometimes gave high values. After the discontinuation of MMI, serum T3 increased over the normal range more rapidly than did T4.