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KOSHI SAITO, KUNIHIRO YAMAMOTO, SHO YOSHIDA, SHIGEO MANABE, MICHIKO SUZUKI, TAKAJI TAKAI, TOSHIKAZU SAITO, TAKESHI KUZUYA, SHIN-ICHI MORIYAMA, Goitrous Hypothyroidism due to Iodide-Trapping Defect, The Journal of Clinical Endocrinology & Metabolism, Volume 53, Issue 6, 1 December 1981, Pages 1267–1272, https://doi.org/10.1210/jcem-53-6-1267
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Abstract
A 32-yr-old man with goitrous hypothyroidism due to an iodide-trapping defect is described. He was admitted because of goiter which had been increasing in size. His parents were unrelated, and no cases of goiter were found in his family. On admission, serum T3 was 39 ng/dl, serum T41 was 1.0 μg/dl, and serum TSH was 217 μU/ml. His 24-h thyroidal 13II uptake was 0.05%. Antithyroid antibodies were negative. In a tracer study, the thyroidal 131I uptakes were 6.3% at 2 h, 4.0% at 6 h, and 0.9% at 24 h after iv injection of the radioiodide. The decline in the neck counts was linear and parallel to that in the serum 131I. The 24-h urinary excretion of 131I was 92%. The saliva to serum and gastric juice to serum ratios of 131I concentrations at 2 h were very low (0.95 and 0.97, respectively). After the administration of iodine (14 mg in Lugol's solution/day for 10 days), serum T3 was 228 ng/dl, serum T4 was 6.8 μg/dl, and serum TSH was 24 μU/ml.
Some biochemical studies were carried out using the patient's thyroid tissue. In a kinetic study on iodide trapping by thyroid slices, the thyroid to medium ratio of iodide concentration in the patient's tissue was constantly about 0.1, in contrast to 1.5–4.0 in a control subject. The microsomal peroxidase activity in the patient's thyroid, assessed by iodination of bovine serum albumin, was about 3-fold that in a control subject on the basis of DNA content. Both ouabain-sensitive and -insensitive thyroidal Na+-K+-ATPase activities were present. These results suggest that the iodide-trapping defect in this patient was due to an impairment in the specific iodide carrier system rather than in the Na+-K+-ATPase itself.
