1231
LATE EFFECTS OF RADIOACTIVE IODINE IN FALLOUT
in 1965, were in the range that we find in
' TABLE 6.
the northeastern United States. In 28 sam-
ples, the 24-hr urine excretion was 19 to
279 wg with a mean of 105 yg. This indi-
cated that there was mo excessive intake of
iodine in the Marshall Islands that might
be related to the iodoprotein in the blood
and, secondly, that there was no deficiency
of 1odine that could be related to the later
development of goiters. The thyroxinebinding capacity of the thyroxine-binding
alpha globulin (TBG) was also measured
in sera with elevated PBI levels, and no
elevation was found. An increase in TBG
could explain an elevated PBI but not a
high serum iodoprotein level.
To conclude with this part of the study,
the detection of a high blood iodine in
Marshallese was an unexpectedfinding, one
that is still not explained. People living in
the Marshall Islands, for reasons that are
not known, have an unusual elevation of
serum iodoprotein.
When Dr. Rall went on one of the expeditions to the Marshall Islands in March
1965, the situation with the abnormal PBIs
was known, and he decided to look a little
TABLE 7.
Column Chromatographic Analysis
of Serum Iodine*
Group
No.
Total
Iodo- Ty + Tat
Samples Iodine protein
—pug/100 ml
Marshallese
North Americans
19
25
7.0
5.1
2.2
0.8
4.5
3.8
* Average values.
} T, = thyroxine, T; = triiodothyronine.
further into the iodine metabolism in these
people. He was more interested in the abnormality in Marshallese in general than he
was in abnormalities that might exist in the
people who were beginning to form nodules
just about this time, and all of these stud-
ies were done on individuals without nod-
ules. There were 21 Marshallese (all adults)
who were studied. Twelve of them were in
the exposed group; 9 of them were never
exposed to radiation. The results presented
in Table 8 showed no difference between
these groups of individuals, and they are
compared with average normal values that
we would find in the United States.
These studies were done with 187]; this
isotope was used because of the very low
Serum Iodoprotein Levels in Relation to Thyroid Function
Case No.
Total Iodine
3
17
1.0
(2.2)
3.1
1.9
(1.9)
1.8
21
1.3
64
69
68
Iodoprotein{
3.2
3.1
65
Thyroidectomized§
59
T,lt
ug/l ml
Hypothyroid§
3
Levothyroxine treated ||
34
PRI*
5.0
5.7
1.8
<0.5
<0.5
2.0
1.7
(1.3)
(>1.3)
(>0.8)
2.9
(4.0)
10.8 [9.1]
6.5 [4.6]
3.2 [3.3]
11.8
5.8
6.0
8.2
5.3
2.8
* PBI = protein-bound iodine.
{+ T4I = thyroxineiodine.
t Iodoprotein Jevels in parentheses are the difference between PBI and T,l levels. The others were measured
directly by the column method.
§ Levothyroxine stopped approximately 3 weeks before sampling.
| Treated with levothyroxine, 0.3 mg/day, for 6 months. Values in brackets are determinations made before
starting thyroxine.
Pepe pan ycneesRee
Volume 66, No. 6
June 1967