The nature of thyroid hormone receptors. Intracellular transport and compartmentalization of chromatin receptors and thyroid hormones

: It is well established that in vivo administered labelled TBPA penetrates into liver, brain and lung cells, is translocated from cytosol into the nucleus and is accepted by chromatin without being affected by modifications touching upon the antigenic determinants of this protein. Electron microscopic autoradiography demonstrated that 125I-TBPA translocated from cytosol into the nucleus is localized on the border between hetero- and euchromatin. The data obtained may serve as an additional proof of the universal structure of intracellular thyroid hormone receptors and suggest that TBPA participate in manifestation of genetic effects of thyroid hormones.