28 devoid of physiological activity. Hence an iodoprotein containing only these iodoaminoacidsis near the normally high Marshallese values (a) in cases which had been on suppressive thyroxine therapy, (b) in cases with atrophic glands due to likely to bealso physiologically inactive. The reason these individuals have such an iodoprotein radiation (subjects No. 3 and No. 5), and (c) in thyroidectomized cases. The source of the iodoprotein is not known. The previously reported finding of high plasma proteins,® particularly gamma globulins, in the Marshalleseis of interest but may be an unrelated phenomenon. It will be important to see in future studies whether the iodoprotein can be labeled with radioiodine. The data on urine icdine show values in the normal range. In general, it had been expected that individuals living close to the sea and eating _ seafood and fish would show relatively higher iodine intake. The inhabitants of the Marshall Islands have fish as one of their main sourcesof animal protein. Furthermore, these people are in the bloodiis not clear. The data on normal controls from the Eastern United States, who showed 0.80 ug% iodoprotein iodine-in their serum,suggest thatit is a normal, albeit minor, constituent. The method of chromatography employed is such that well under 5% (or 0.2 ug%) of serum thyroxine iodine appears in the unretarded oriodo- protein fraction. Therefore, the finding of iodo- protem does not appear to be a methodologic artifacts”.. More)recently, with the developmentof thyroid abnormalities in the exposed Marshallese (to be described), it was possible to examine serum iodo- protein levels in cases with thyroid hypofunction. These data are presented in Table 16. It seems constantly exposed to sea spray, since the island at its widest is about 4 mile across, and its highest likely that the source of the iodoprotein was largely cxtrathyroidal,since the levels of lodoprotein.were “oes om my my ere ae a Set org . - ae “TableTS ea £, so ae Me ti ~ ‘i sl Sa TM Subject Total “jodine, No. vail “JBI, 7, iialize, me“odin” wee eS: anit “Kr ~ 1.8 "3,1 e.9 oe 3 yl idectamized** Srp * <05 “a 5 ale we.| pe gn 90 17 (>! fon - fday proposed by R: 7 “s 3 ‘eigiecradation asd the sameé-voliiiie of . aiatoaionaethyridline atiditis assumede8%ave inthe thyroid gland:‘thenorferwoulg ex- thyroidisto: getie te-eFghnic ali eprQieriodal to thielevetst organic iodine a) ‘ehfim. Additiesio “te naceprerein rein iodine ets for 3.2 (45) 3.8 [2.9] Me et etfindependentlyfrei 3 ‘ei ee é a roll }ma serepresent the differpee TPS gags cee eothers were meaPt ras $3 eaa eetieads ley is kiinivn aout theatestturn- sigfum'TedeproteinithasToughly the = aS pee [4-6] x. 6.0 [2.5] i ee to the -Unfertu- (48) po 3eS. , by Stanburyet aha Soiand-by P3 reinkelhd Ingbar** ‘overt ee r+ Supetumerc = aie + 3.2 ~ 1.0 i e= 3.1 arpunval-ibdinefecreted daily ti’ Thévalue danfissomewhat Higher: 5 pg/daySoke Fe“epicin twere asedawiththe resuiggobtalnvedwith Terudits to calculatethe mee = hale Sem lodopistein Levels in Relatioggys Toss _to Thyroid Fageson ee _ point is 20 ft above high tide. - -#¥lec @8tazpn he, andis compatible: ao *"1.TRyroxinte stoppedsever alsWORESefore sampling. {Treated with v-thyroxine, 0.2 mg per day, for 6 months. Values in brackets are determination made prior to starting thyroxine treatment (1965). mee : andelevated thyroid10¢ ine secretion rate. ever, as noted above,it seems somewhat morelikely that the serum iodoprotein is not of thyroidal origin.