[Formation of iodotyrosines and iodothyronines in low iodinated human thyroglobulin fractionated by isopycnic ultracentrifugation].

Iodotyrosines and iodothyronines formation have been studied in thyroglobulins (Tg) extracted from porrly iodinated human thyroid tissues. After centrifugation in RbCl density gradient, various protein fractions containing different amounts of iodine have been isolated from pure Tg. The results indicate that, even after fractionation of Tg, the synthesis of thyroid hormones takes place at a very low level of iodine content. This suggests that the Tg fractions are still heterogenous and contain a large proportion of non-iodinated molecules.