SERUM “THYROGLOBULIN” IN THYROIDAL CARCINOMA*

Abstract
The butanol-insoluble radioiodine (BII131) in the serum of 34 patients given therapeutic doses of radioiodine was analyzed. In addition to the 2 recognized iodoproteins[long dash]one associated with the serum albumin (compound X) and one located between the electrophoretically separated alpha globulins (thyroglobulin)[long dash]2 additional "thyroglobulins" in the serum were observed. One of these was associated with the alpha1 globulins, the other with the alpha2 globulins. In a series of 24 patients with carcinoma of the thyroid, the albumin type and the alpha-globulin types of radioiodinated serum protein were found with about equal frequency. So far, in our experience, the alpha-globulin BII131 has not been detected in any patient not having carcinoma of the thyroid gland. Only the albumin type of radioiodinated protein was found in the serum in 8 patients with exophthalmic goiter, 1 with Hashimoto''s disease and 1 with a normal thyroid gland. Unexpectedly, quantitative analysis of the serum BII131 revealed that, on the average, as much of these thyroidally derived proteins was found in the serum after tracer doses of I131 as after therapeutic doses in the patients with carcinoma. Wide variations from this average were noted in individual cases. The current concept that the concentration of thyroglobulin in the serum is a function of the intensity of radiation to thyroidal tissue is questioned.