THYROID COLLECTION OF RADIOACTIVE IODIDE AND SERUM PROTEIN-BOUND IODINE CONCENTRATION IN SENESCENCE, IN HYPOTHYROIDISM AND IN HYPOPITUITARISM*

Abstract

The uptake of radioactive iodide by the thyroids of 160 apparently euthyroid and 13 hypothyroid or hypo-pituitary patients was studied. The level of serum protein-bound iodine was detd. in selected cases. In the male, there is a gradual drop in the mean gradient from puberty to senescence. In the female there is a sharp drop in the mean gradient, after the menopause, to low levels. There is no sex difference in the mean gradients at puberty; however, after puberty, the mean gradients in the female are consistently higher than in the male. The decreased gradient is not associated with a decreased concn. of circulating protein-bound iodine. The accumulation gradients tend to be low in hypothyroidism and in hypopituitarism; in these diseases, they are associated with a subnormal conc, of serum protein-bound iodine.