Table 7. Results of serum analyses in exposed Marshallese subjects with at least two TSH assays >6 W/ml (1980). Sub ject No. & sex Date of sample Serum TSH (W/m) 3M 5M 4M 1977 1963 1972 69 500 6.0 2.5 0.5 7.3 1969 1979 1974 1979 1974 1977 1977 1979 1980 6.3 6.5 6.3 8.3 10 7 6.6 8.8 7.3 4.4 4.9 7.1 8.0 4.2 5.2 6.1 7.6 5.1 16M 34F 71F 78F 32M 1974 Serum Ty, (Ue/d1) 7.9 Normal control range: 0-6.0 Age at exposure Estimated thyroid dose (rads) 0.95 0.71 -- l 1 38 1150 1150 335 0.89 0.91 -0.74 -0.98 0.82 0.68 0.89 39 135 4&5 335 27 335 37 335 3 1050 TBGI (units) 5.4 0.82 5.0-10.2 0.85-1.10 observation of elevated TSH in the individuals listed in Table 7 cannot be attributed to age alone. No. 4 and No. 78 were among those in whom TSH stimulation tests had been performed earlier. Both had Ty, increments of “1 Ug/dl 24 hours following 10 units TSH administration, a clearly subnormal response showing that these thyroids had no capacity to respond to increased demand. To evaluate the pituitary/thyroid axis more completely, TRH studies were done in some individuals. Results on subjects No. 4, 71, and 78 are given in Figure 5. Data from subject No. 74, discussed below, are also shown. This patient had surgery subsequent to the test and is therefore categorized separately (Table 8). Subjects No. 4, 71, and 78 all were hyperresponsive to TRH stimulation, with serum TSH values at 20 min >22 WU/ml, which is the 97.5% con- fidence interval for mean normal responses in the Marshallese. 90. . 40; i ‘ 1 Figure 5. Basal plasma TSH and TRH- =r 78 fo a ¢ 20+ stimulated TSH in euthyroid Marshallese and in four exposed subjects with biochemical evidence of impaired thy- * 0b 20 min after infusion of 500 Ug TRH. The upper limits of the normal range 4 tot Or ao aTane . . roid function. * Plasma was obtained are indicated by the shaded bars. -~72-