Protein-bound iodine in extrathyroidal tissues

Abstract

A method is descr. and its limits of error pointed out. In normal dogs the concn. of protein-bound iodine (PBI) in the serum is higher than in skeletal muscle and lower than in liver and kidney. No significant difference was found between the concn. of PBI in the serum and that in the heart, lung, spleen, small intestine, pancreas and testis. The feeding of powdered thyroid or iodide to normal dogs caused an increase in the concn. of PBI of all tissues studied. PBI is probably partly intracellular in the dog. In rat liver PBI occurs in approx. equal concns. in the nuclear, mitochondrial, and supernatant (cytoplasm plus extracellular fluid) fractions.