Iodide organification defect in iodine deficiency endemic goiter.

In 17 goitrous persons in an iodine-deficient area, in 23 nongoitrous inhabitants of the same village, in 10 goitrous persons in Athens, and 8 normal controls the perchlorate discharge test was performed, either in the simple standard form or after pretreatment with either 0.5 or 2.0 mg potassium iodide or 2.5 mg carbimazole. With the simple test or with 0.5 mg potassium iodide, there was no significant discharge in any group studied. With 2.5 mg carbimazole, there was a profound discharge of the trapped iodide in both groups in the iodine-deficient area. With 2.0 mg potassium iodide, however, there was a clear discharge in the two goitrous groups (i.e. the one in the endemic area and the second in Athens), a less pronounced discharge in the controls studied in Athens, and no discharge at all in the nongoitrous inhabitants of the iodine-deficient endemic area. These findings provide evidence for an abnormality present in the patients with endemic goiter, most probably faulty iodine utilization due to impaired organic binding. The nongoitrous persons in the endemic areas, on the other hand, seem to be even more efficient in handling the trapped iodide than the controls studied in Athens. These findings may provide an explanation for previous observations that in endemic areas only part of the population develop a goiter, whereas the others adapt successfully to iodine deficiency without significantly enlarging their glands.