EFFECT OF LARGE DOSES OF RADIOIODINE ON THYROID FUNCTION

The effect was studied of large doses of radioiodine on the relative amounts of various organic iodine compounds present in the thyroid glands of rats. At 24 hours there was no effect of radiation from 131I on the relative amounts of diiodotyrosine, monoiodotyrosine, and thyroxine plus triiodothyronine found in the gland. After 48 hours and 5 days, during which time there is known to be considerable destruction of epithelial cells, there was an inhibition of thyroxine synthesis but not of the iodination of tyrosine. There is evidence that even at some days after irradiation at the levels used some follicles are preserved and able to synthesize hormones.

CHROMATOGRAPHIC AND ELECTROPHORETIC SEPARATION OF THYROID HORMONES AND SOME IODINE-CONTAINING ORGANIC COMPOUNDS

In order to separate some organic iodine-containing compounds, which elevate the protein-bound iodine in the serum, from the normally occurring thyroid hormones and their derivatives, certain one- and two-dimensional paper chromatographic and electrophoretic systems were used.

Two-dimensional chromatography gave the best in vitro separation and some exogenous iodine-containing substances (iopanoic acid and its sodium salt, diatrizoate sodium, iodochloro-oxyquinoline and benziodarone) were satisfactorily separated from iodide, thyroxine and triiodothyronine, which are normally expected to be present in the serum.

A few experiments were carried out on patients who had been subjected to cholecystography after an oral dose of the sodium salt of iopanoic acid (Bilijodon Natrium®, Leo). The two-dimensional chromatography system was combined with the sensitive staining method developed by Gmelin & Virtanen (1959) so that the normal iodide constituents in the serum could be detected from samples of 3–6 ml of serum in all control cases. In the cholecystographied cases, the iopanoic acid was detected as a clear spot.