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
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nation for the dillerence in scrum Ty concentratiuns between the larger groups of Rongelap and
Cuirik subjects; however, these results are based
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The results of these analyses provide ne expla-
biden, Se RTOl laAG eee yt
and five were known to be pregnant, a condition
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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,
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