THE METABOLISM OF IODOTYROSINES. II THE METABOLISM OF MONO- AND DI-IODOTYROSINE II CERTAIN PATIENTS WITH FAMILIAL GOITER*

Abstract

Iodinated components appearing in the serum and urine of 3 patients with familial goiter and hypothyroidism were observed after administration of I131 and I131-labeled mono- and di-iodotyrosine. After administration of I131, labeled mono- and di-iodotyrosine and at least 2 other unidentified components appeared in serum and urine. One of the unidentified components yielded mono-iodotyrosine upon hydrolysis. Intravenously administered dl-mono-iodotyrosine was excreted in the urine either unchanged or as unidentified substances. One of the latter yielded mono-iodotyrosine upon hydrolysis. A small fraction of the injected labeled mono-iodotyrosine was deiodinated. Intravenously administered I131-labeled dl-di-iodotyrosine was excreted in the urine almost entirely unchanged. There was no evidence for any deiodination. A small portion of the injected di-iodotyrosine was not accounted for at the end of 24 hours. Five euthyroid relatives (4 with goiter) of one of the patients with congenital goiter and hypothyroidism, were studied after administration of I131-labeled dl-di-iodotyrosine. Although these patients deiodinated di-iodotyrosine, a larger fraction of the injected dose was excreted unchanged in the urine than in a group of 15 patients simultaneously studied but previously reported.