Activity of iodotyrosine deshalogenase in "normal" and diseased human thyroids.

Abstract

ABSTRACT Iodotyrosine deshalogenase assays were performed on 40 surgical specimens from 39 human thyroid glands. Histologically normal thyroid tissue from 8 patients with thyroid cancer served as “normal” controls. The iodotyrosine deshalogenase activity of thyroid tissue from 10 patients with colloid adenomatous goiter and 5 patients with Hashimoto's struma was within the range of activity found in “normal” thyroid tissue. Iodotyrosine deshalogenase activity was significantly lower (P <0.02) than “normal” in the thyroid glands of 2 patients with nonspecific thyroiditis. A clearcut difference from “normal” activity (was not found in the thyroid glands of 8 thyrotoxic patients rendered euthyroid with propjdthiouracil and Lugol's solution. The Michaelis-Menten constant for iodotyrosine deshalogenase in the thyroids of these thyrotoxic patients did not differ significantly from “normal” (2.3×10−5 Mand 1.8×10−5 M, respectively). The mean iodotyrosine deshalogenase activity in carcinomatous tissue from the thy...