Effect of iodized oil on iodine content, thyroglobulin maturation and on biochemical constituents of endemic goitre in brazil.

The biochemical and morphological changes in thyroid glands were studied in 5 patients with endemic goitre in the region before and one year after the administration of iodized oil. Each patient received a tracer dose of 125-I 3-5 weeks before the biopsy and another tracer of 131-I 12 h before surgery. It was observed that: 1. Iodine deficient goitrous glands had more protein per gram of tissue and that this was corrected by iodination. 2. The goitrous glands exhibited a higher relative proportion of particulate iodoprotein that incorporates more labelled iodine in relation to time of labelling. This abnormal situation is reverted to normal by iodination. 3. A significantly higher proportion of T3 + T4 is synthetized by the glands treated with iodized oil. 4. The increased amount of 127-I per gram of tissue is followed by an increased iodination level of thyroglobulin. 5. The ultracentrifugal pattern of proteins observed for iodine deficient glands differed from the iodinated glands, indicating a failure of maturation of thyroglobulin and possibly a greater than normal degree of heterogeneity. 6. The shift in sedimentation pattern was clearly induced by the increased degree of iodination, as shown by the iodized oil injection. 7. The increased cellularity and the higher rate of protein synthesis in the goitrous glands are reverted to normal after the iodized oil injection.