Continued Protocol 1974 Page Four Therefore may be important in cases that might develop cardiac problems. this group will be taken off thyroxine prophylactic treatment beginning (The 23 people who have had January 15, 2 months before the survey. thyroidectomys including the 2 boys with thyroid atrophy, will not be included in this study since it is already known that their thyroid function is *sbnorral and continued thyroid treatment is of great importance in this group.) In order to test thyroid function in this study it is planned to measure thyroxine (T-4 and T-3) and TSH levels on an initial blood sample followed by administration of 10 units of TSH and another blood sample drawn 24 hrs later for measurement of thyroxine levels and clinical exam of the thyroid. About 10 unexposed Rongelap people will be similarly tested. Dietary lodine and Iodine Excretion Levels: JIodine in the diet may be evaluated by testing the level of this element in representative meals which will include local fruits and marine life. It has always been thought that the iodine level in their diet should be high and this will test this assumption. Urinary excretion of iodine, tested some years ago, was in the low-normal range and this test will be repeated on aliquots of 24-hr urine samples being collected for radiochemical analyses. These studies may also be done in some of the Utirik population since their diet is presumably less 'westernized",. There are two other thyroid studies which may require some supplementary information: (1) excretion rate of iodine in children using 1291 is in progress. Activation analysis for measurement of urinary iodine on urines from 2 children given this isotope is being measured up to 16 days. This study is designed to help evaluate the thyroid dose received by children which has been based on an excretion rate of 0.1% of thyroid burden being excreted in the urine at 15 days after exposure (the time of the first urine collections). The other study (2) is an evaluation of iodoprotein levels which are unusually high in the Marshallese people. Jack Robbins, Ed Rall and I are particularly interested in investigating the environmental and genetic aspects of this finding. Other ethnic groups are under study. One study in progress concerns the use of orally administered !29[ with plasma collection before and at 2 and 4 days to determine possible incorporation of orally ingested iodine in the various serum iodine fractions. This study is of a preliminary nature and depending on the outcome, further sampling of the population may be indicated. Diabetic Study: Diabetes in the Marshall Islands, along with cataracts, is considered to be of unusually high incidence. The Trust Territory Medical Personnel at the district centers have been quite concerned about the problem and have requested our help in any way possible. In response to this request, although we have not seen any connection between diabetes and radiation exposure in the Rongelap people, we are anxious to help if possible. We are therefore fortunate in having Dr. James Field, an expert in this field, participate in the survey and perhaps suggest further procedures for evaluation and therapy of this disease in the Marshalls.