NATURE OF THE I¹³¹COMPOUNDS APPEARING IN THE THYROID VEIN AFTER INJECTION OF IODIDE-I¹³¹12

Abstract

THE work of many investigators has established that the major circulating thyroid hormone is thyroxine (Taurog and Chaikoff, 1948, 1950b; Laidlaw, 1949; Rosenberg, 1951;Dingledine et al., 1955; and others). Evidence for this is based primarily on the chromatographic analysis of plasma obtained from animals previously injected with I131. The presence of I131-triiodothyronine in such plasma has also been reported (Gross and Pitt-Rivers, 1952; Roche et al., 1952a, Dingledine et al, 1955) but the concentration of this component is usually very small, and in our laboratory it has, until recently, escaped detection. In the thyroid gland itself, several iodinated amino acids are known to be present. These include monoiodotyrosine, diiodotyrosine, thyroxine, triiodothyronine, and quite possibly other iodinated compounds (Roche et al., 1955a; 1955b). The iodinated amino acids are bound together, with other amino acids, in peptide linkage to form the unique iodinated protein of the thyroid gland, thyroglobulin. Rel...