Iodoproteins in normal and abnormal human thyroid tissue and in normal sheep thyroid.

Abstract

Two typos of iodoprotcins other than thyroglobulin have been found in normal and abnormal human thyroid tissue and in normal sheep thyroid. They are similar to, but not identical with, iodoproteins previously described in a functioning rat thyroid tumor, and were detected in tissue labeled with I131either in vivo or in vitro. One of these iodoprotcins, termed “participate iodoprotein” or “P-l” was not extractable from thyroid homogenates with 0.15 M NaCl. It comprised from 1 to 6% of the organic radioiodinc in normal thyroids and in several abnormal thyroid tissues, but was 37% in a follicular carcinoma. The second iodoprotein, termed “S-l iodoprotein,” was soluble in 0.15 M NaCl, but differed from thyroglobulin in other physical properties. It was more soluble than thyroglobulin in phosphate buffer, scdimented more slowly in the ultracentrifuge, and had a faster electrophoretic mobility. It comprised from 1 t o 7% of the extractable organic radioiodinc in normal and in a wide variety of abnormal thyroids...