131I uptake of one-day old chicken endodermal organs.

In the one-day old chicken, the organs of endodermal origin, these the thymus, trachea, lung, and intestine take up significantly more iodine than the muscles which are of mesodermal origin. The thymus shows an especially high iodine incorporation, amounting in absolute values to that of the thyroid gland. An organ accumulates the more iodine, the closer to the thyroid its anlage is situated and vice-versa.