Circulating Iodoprotein in Two Patients with Autonomous Thyroid Nodules

ABSTRACT Two euthyroid patients with autonomous thyroid nodules are presented in whom an abnormally large percentage of the circulating protein-bound Il3l-labeled material was not soluble in acid butanol. Chromatography and pancreatin digestion characterized this material as an iodoprotein. Electrophoresis showed that it migrated with the serum albumin. Subsequent electrophoresis of a saline extract of the nodule excised surgically from one of the patients showed an abnormally large amount of albumin-migrating iodoprotein. Since the scintigraphic studies clearly indicated that the nodule had completely suppressed the remainder of the gland, it is assumed that this circulating iodoprotein originated within the autonomous nodule.