LATE EFFECTS OF RADIOACTIVE IODINE IN. FALLOUT in 1965, were in the range that we find in the northeastern United States. In 28 sam- TABLE 6. . ples, the 24-hr urine excretion was 19 to Column Chromatographic Analysis of Serum Iodine* Group 279 wg with a mean of 105 pg. This indi- No. Total Todo T. + Tif Samples Iodine protein cated that there was no excessive intake of iodine in the Marshall Islands that might be related to the iodoprotein in the blood and, secondly, that there was no deficiency of iodine that could be related to the later development of goiters. The thyroxinebinding capacity of the thyroxine-binding alpha globulin (TBG) was also measured in sera with elevated PBI levels, and no elevation was found. An increase in TBG could explain an elevated PBI but not a high serum todoprotein level. To conclude with this part of the study, the detection of a high blood iodine in Marshallese was an unexpected finding, one that ts still not explained. People living in the Marshall Islands, for reasons that are not known, have an unusual elevation of serum lodoprotein. When Dr. Rall went on one of the expeditions to the Marshall Islands in March 1965, the situation with the abnormal PBIs was known, and he decided to look a little TABLE 7. Case No. Total Iodine North Americans 25 +pg/ 100 mi 7.0 2.2 5.1 0.8 4.5 3.8 * Average values. ft Ts = thyroxine, T, = triiodothyronine. further into the iodine metabolism in these people. He was more interested in the abnormality in Marshallese in general than he was in abnormalities that might exist in the people who were beginning to form nodules just about this time, and all of these studies were done on individuals without nodules. There were 21 Marshallese (all adults) who were studied. Twelve of them were in the exposed group; 9 of them were never exposed to radiation. The results presented in Table 8 showed no difference between these groups of individuals, and they are compared with average normal values that we would find in the United States. These studies were done with 1873; this isotope was used because of the very low PBI* 3.2 3.1 3. 17 1.8 24 64 Tilt Iodoproteint 10.8 [9.1] 8.2 11.8 1.0 1.8 1.9 <0.5 (2.2) (1.3) (1.9) (> 1.3) 1.3 <0.5 (>0.8) 5.7 1.7 (4.0) 6.5 [4.6] 3.2 [3.3] 5.0 69 59 68 19 ug/l00 ml 5 65 Thyroidectomized§ 34 Marshallese Serum Iodoprotein Leveis in Relation to Thyroid Function Hypothyroid§ 3 Levothyroxine treated]] 1231 2.0 5.3 5.8 2.9 2.8 6.0 Ee TE Ter ae eee ‘Volume 66, No. 6 June 1967 * PBI = protein-bound iodine. } Tal = thyroxine iodine. {t Iodoprotein levels in parentheses are the difference between PBI and Til levels. The others were measured directly by the column method. starting thyroxine. re se ee pee ee § Levothyroxine stopped approximately 3 weeks before sampling. { Treated with levothyroxine, 0.3 mg/day, for 6 months. Values in brackets are determinations made before