F, IODOPROTEIN STUDIES Analyses for protein-bound jedine ins sera of Marstiallese people revealed a level signiticantly higher than that scen in North America" 2" Sub. sequent studies showed that this clevation could be atinibuted to an increase in dhe jedoprotein frac- on highlyselected sampling and dherelore are not representative of the island groups yt whole. Ex. amination of jadividual Cook and Rowduelap plasmas suggested that low Ty concentrations were associated with relatively low TU BG values. ‘To study the interreladonship of Ty binding and TG fevels in greater detail, the dialyzabbe fractens of T, (DFT) were determined ina number of plasma samples with low, normal, or elevated TBG-binding capacities. Phe results are presented in Table 31. Pnsubjects with tow TiG, the mean DEP, was greater than in subjects with normal or elevated TRG. Vhe absolute free Fy was nod dil: ferent in the three groups, which indicated that the abnormal Ty levels ameng these subjects re- tion aad indicsted tbat this was responsible for ia correct evaluation of thyraid function during the carly vears of the surveys. This unusuai finding pronipted us ta determine seria todoprotens wveds inseveral other Pacific Isands vroupes (sco Vable W2). Except for a group of Americans living on Rowajaleis Atoll, these groups also exhibued bigh serum levels of iadopratcin. The Maui group wos comprised of persons of alvvost pure | Rawaiiaa ane cestry, some of whorn ate seaweed in large quia uty, but the jodoprotein devel did) not correlate with this dietary intake, In the Rongelap populatien, itis of interest thatthe jadoprotcin level retained bigh in dwo athyrcotic boys; afler subtotal thyroidectomy: aad during thyroid: suppression by thyroxine adaiinistration-" Vhis strongly implies an extrathyroidal (endogenous) ara dietary (exo fect alterations in phoma bormose binding rather enous) source for the iadoprotein, Phe couse of the elevation, hawever, lias not been ascertained. all the subjeces with bow plissna Ty concentrations in the larger Ctirik and Rongelap groups had nor: inal plasma ‘TSE, we would expect a more systes lo organify iodine duging phagocytosis!) Alba the Marshallese do not have aausually bigh lous than in thyroxine production tates. Since virtually atic study of THO levels by REA to show a One possibility is that itis produced: ia poly. morphonuclear leukocytes. Phove cells are knewn koevie counts, they do have a tild cusinapliilia Vale 2 Serum fadoprotets Laevels (ay) in Pacific Isto Populations and in Americans Group Na, ured Rongelap exposed Sa Uivsaid necules Thyroid atrophy Phyrekd nodules, peep HH} ‘Votald Pmt 2 Kil hakoprotcin hose 2H=04 L2mus DOE nie t] Tua hizha Jt S708 7 hat bu Uirik Kongelap unexposcd Ka punyiarasye 4 2 ai tobe HT 2d Hoe SAP EAL Lota Tet eade a S07O04 Americans: Kwajalein Bs 64245 $US 1 Leet Mier partial thyeeider tui Afiee total diy tr nidoutny Atlingnae Pingalap Viana (Miavui) US. “ J 1 7 he ine HIzLI o bods ails oo mee ete toch bt Veil hitos Sete: » nation for the dillerence in scrum Ty concentratiuns between the larger groups of Rongelap and Cuirik subjects; however, these results are based Beene tWgte 6 aae a that can elevate the scrum “PRG. The results of these analyses provide ne expla- biden, Se RTOl laAG eee yt and five were known to be pregnant, a condition 1 epee ET aye>. higher frequeneyof low TBG levels in the Cririk group, Such a study is currently i progress, bound per mole TBG, the expected ratio is 777000 pg/57000 ing = 15.6, The results of these analyses are summarized in Table 30 and Figure 40. There was no significant dillerence in TBG berween the Rongelap and Utirik groups or between the exposed and unexposed Rongelap groups. Eight subjrots had high TSG levels. These were all females, St oe ee histo