THYROGLOBULIN IN THE LYMPH DRAINING FROM THE THYROID GLAND AND IN THE PERIPHERAL BLOOD OF RATS

Publisher Website
Google Scholar
Abstract
It has previously been thought that organic iodine leaves the thyroid gland only in the form of iodoamino acids which are derived from the breakdown by the thyroid cells of the thyroglobulin stored in the colloid. It has now been shown that a considerable amount of iodoprotein also leaves the thyroid gland in the thyroid lymph and that most, if not all, of this iodoprotein is actually thyroglobulin. The iodoprotein in the thyroid lymph was studied by two different techniques, either by chemical separation of iodoprotein after giving the rats relatively small doses of 125I‐inorganic iodide or by measuring the amount of thyroglobulin by an immunoassay, which avoided the necessity of giving the animals radioactive iodine in vivo.The iodoprotein content of the thyroid lymph is raised sharply by giving the rats thyroid stimulating hormone and also by thyroid massage which expresses the lymph contained within the lymphatics of the thyroid gland. Iodoprotein is virtually absent from peripheral lymph (i.e. lymph not containing any thyroid lymph). The peripheral blood of rats also contains small but appreciable amounts of thyroglobulin.The implications of the presence of thyroglobulin outside the thyroid gland are discussed.