Synthesis of thyroglobulin in thyroid carcinoma patients after radioiodine therapy

Abstract

Endogenously radioiodinated thyroglobulin (T_g) and the serum concentration of T_g have been measured in patients with metastatic thyroid carcinoma after therapeutic doses of radioiodine. Serial samples of blood were analyzed for both these parameters over a period of 10 to 22 days. The specific activity of T_g (cpm/ng) was calculated for each sample. Among the six patients studied, three showed constant specific activity. The specific activity of the other three fell, indicating the entering of newly synthesized T_g into the circulation. The respective amounts of T_g entering into the circulation in these three patients were 120, 852, and 20,935 ng/ml serum/day.