THE METABOLISM OF IODOTYROSINES. I. THE FATE OF MONO- AND DI-IODOTYROSINE IN NORMAL SUBJECTS AND IN PATIENTS WITH VARIOUS DISEASES*

Abstract

Mono- and di-iodotyrosine (T1 and T2) are important intermediary substances in the synthesis of thyroid hormones by the thyroid gland. It is generally presumed that these are precursors of thyroxine and tri-iodothyronine. The T1 and almost all of the T2 of the gland are in peptide linkage in the thyroglobulin (1). Normally they do not escape into the general circulation. There has been little reason to suppose that these two substances play a role in the metabolism of iodine outside the thyroid gland.