35 TSHconcentrations were normal. For this reason, TBG-binding capacities were determined in a numberof subjects with abnormal Ty, values. TBG analvses were done on sera from 536 subjects (25 Rongelap and 31 Utirik) selected as representative of three groups: people with low, normal, or high plasma T4 concentrations. Two methods were used: TBG was measured byradioimmunoassay (M.C. Gershengorn and J. Robbins, unpublished observations, 1974) and TBG-binding capacity by reverse-flow paper electrophoresis. The results were comparable since the meanratio of TBG-binding capacity (ug T,/dl) to TBG (mg/dl) was 13.9. On the basis of one mole T, Table 31 Total and Free Thyroxine, Thyroxine- Binding Globulin, and Thyrotropin Levels in Marshallese TBG, pg/dl Ty, pedi Subjects with TBG-bind capacity <14 pe T,/dl 827 7.6 (1.06)* 5.1 917 981 2115 2126 2144 2174 1.72 1.55 1.43 - 77 9.1 7.0 4.4 4.9 4.0 3.21 3.20 3.76 t4t 1.57 1.50 < 1.0 <5.0 - 48 3.23 1.55 <1.0 1.29 <2.5 - Mean S.D. 9.02 *+2.39 4.1 850 14.0(1.04) 2137 19.9 (1.37) 2212 20.1 2232 16.2 (1.54) 2168 14.4 2230 2206 2182 2218 2221 17.7 14.4 14.3 13.6 2257 17.3 2136 * ° 0.998 1.12 4.34 3.33 1.44 4.6 S.D. O1f 3.08 9.2 2.90 7.4 5.0 3.0 4.8 2.77 2.92 3.04 2.68 8.8 2.94 ° 5.0 48 Mean S.D. 2.94 1.84 2.42 1.42 1.79 2.67 16.65 5.9 2.60 1.53 +2.58 +1.87 +0.503 0.597 2.6 L.14 1.66 2.8 <2.5 3.6 <5.0 2.0 <2.5 2.1 4.9 2.01 1.53 1.81 0.903 2.4 10.8 13.6 0.872 1.19 - 11.03 1.42 1.43 +0.468 +0.358 56.1 (4.56) 12.9 32.8 31.8 7.0 18.2 *TBG by RIA, mg/ml. 2.1 6.0 2.57 0.885 +9.62 2.6 1.16 2.05 1.46 0.912 1.29 1.45 43.5 4.2 3.6 <2.5 6.1 2.15 <2.5 0.92 21.9 (1.28) 7.7 3.1 2.3 + 0.230 2.72 47.6 (3.92) 2217 2256 +0.40 46 6.1 Subjects with TBG-binding capacity >26 ug T4/dl 2138 37.0 (1.52) 9.0 2229 33.7 5.9 891 2.80 4.2 15.3 (1.06) ‘Mean 1.73 3.12 2.94 *+0.543 15.5 4.23 3.2 3.8 Subjects with TBG-binding capacity 14 to 26 ug Ts/dl 2135 3.37 3.53 3.24 13.7 11.9 (0.94) 2183 TSH, pU/ml 4.4 4.4 11.1 (1.03) 220 2248 Free Ty, ng/d) 7.0 (1.20) 8.0 (0.69) 7.1 2193 DFT, x 10+ *+4.63 1.22 1.88 0.991 t.54 1.32 1.80 2.1 2.7 4.4 tee CN a en Subject No.