Simultaneous detection of thyroglobulin (Tg), thyroxine (T4), and Triiodothyronine (T3) in nontoxic thyroid tumors by the immunoperoxidase method.

In 97 nontoxic thyroid tumors, detection of thyroxine(T4) and triiodothyronine(T3) was attempted by the immunoperoxidase method. T4 was demonstrated in 58 tumors (59.8%) and T3 in 76 (78.4%). The feasibility of biosynthesis of T4 and T3 by such tumors was thus established. In 65 of the tumors, we applied the immunostaining method to serial or semiserial sections to study the correlation among the localizations of thyroglobulin(Tg), T4, and T3. The localization of T4 agreed relatively well with that of Tg, and part of the Tg-positive structure frequently revealed simultaneous positive staining for T4. The localization of T3, however, did not always correspond with that of T4 or Tg. T4 and T3 with localizations identical to that of Tg may be considered to be bound to Tg, but the mode of existence of T3 without correspondence in localization to Tg remains unknown.