RELATION BETWEEN THE HYPOPHYSIS AND THE THYROID GLAND EXPERIMENTS WITH RADIOACTIVE IODINE

Abstract

When 1131 (presumably as iodide, although not specifically so stated) is injd. in large doses (3-4 me) into adult rabbits, the largest accumulation of 1*31 occurs in the thyroid gland. Radioautographs of the pituitary show the next highest concn. to be in the pituitary. The distr. of the I131 is uniform in the entire hypophysis at first, but by 7 hours after the injn., almost all of the I131 is in the posterior lobe of the pituitary. The authors believe this time relationship is best explained by the fact that it takes about this length of time for thyroxine to get labeled by the thyroid and excreted into the blood. The localization of I131 to the posterior lobe did not occur in thyroidectomized rabbits.