IODINATED COMPOUNDS IN THE SERUM, DISAPPEARANCE OF RADIOACTIVE IODINE FROM THE THYROID, AND CLINICAL RESPONSE IN PATIENTS TREATED WITH RADIOACTIVE IODINE*†

Abstract

THERE is general agreement that most of the organically bound radioiodine in the blood after therapeutic doses of I131 is comprised of thyroxine. The presence of significant amounts of butanol-insoluble organic iodine, diiodotyrosine, monoiodotyrosine (1), and triiodothyronine (2, 3) has been reported. It is not definitely known whether the appearance of any one, or all of these compounds results from the effects of radiation on the thyroid gland. It is the purpose of this report of work in progress to describe studies dealing with possible relationships between the iodinated compounds appearing in the serum, the rate of disappearance of the radioiodine from the thyroid, the amounts of radiation delivered to the gland, and the clinical response to therapy. Chromatographic fractionations of serum radioiodine extractable in n-butanol were made after 34 therapeutic doses of I131 in 31 patients. Most of the patients had Graves' disease, but 1 with toxic nodular goiter, 1 with metastatic thyroid cancer following surgical thyroidectomy, and 2 with thyroid remnants following surgery for thyroid cancer are included.