Serum Protein-Bound Iodine—Rall and Conard
884
TABLE I
SERUM IODINE
Per
1959
Group
Marshallese
No.
Samples
Range
Serum Protetn- Bound lodines
6.2
4#.1- 9.2
Marshallese
Medical team
1959
Serum Butanol-Exiractable Iodines
Marshallese
4.9
2.7 8.7
1965
1965
Marshallese exposed
Marshallese controls
8.6
4.9
12
1962
1964
7.6
7.0
4.6-12.9°
2.5- 6.9
14
10
4.1-11.9
3.9-10.7
31
19
cent
Over
8 yg.
16
64
0
42
28
12
4
Serum Iodine Chromatography
Total
Group
Todine
Iodoprotein
Ta + Ts
{av.}
Samples
6.98
5.09
2.22
0.80
4.53
3.76
19
25
fav.)
Marshallese
Americans
({av.)
No.
All values are micrograms of iodine per 100 milliliters of serum.
the total iodine is not markedly greater than
the PBI and by the normal levels obtained in
1964 on members of the medical team, whose
blood was obtained at the same time and
under the sameconditions as that of the natives.
The increase in PBI could be due to several
factors. It could be the result of a general increase in serum PBI in all of the population
or it could be due to the occurrence of some
genetic difference so that a substantial fraction of the population has abnormally high
PBI levels and the rest of the population
normal levels. In the first case, a distribution
curve of level of PBI versus number would
show a normal distribution except that the
whole curve would be displaced about 2
pg. per cent upwards. In the second case, the
distribution curve would be bimodal and a
family tree would show familial clustering—
the precise type depending on the manner of
inheritance. Figure 1 shows a distribution
curve of PBI level versus incidence at that
level; there appears to be a single peak with
TABLE II
URINE IODINE*
Date
Method
Average
Range
No,
Samples
1965
Boston Medical
Laboratory
105
195-279
28
* Micrograms per day,
6
8
10
PBI 9/100 mi.
12
Fia. 1
"12.143
no evidence for a bimodal distribution. The
low number of PBI values from 7.75 to 8.0
pg. per cent seems to be due to statistical
variation from the small numbers of cases.
Furthermore, the elevated values, defined as
those above 8.0 wg. per cent, did not show a
familial pattern of distribution. It appears, therefore, that the elevation in the PBI levels is a general phenomenon affecting all the population.
The difference between PBI and BEI in
twelve cases was 1.6 wg. per cent, which is
somewhat greater than an average value of
0.6 wg. per cent [7,8]. This was suggestive
evidence for the presence of iodoprotein in
serum. The results obtained by column chro-
matography substantiate this since an average
iodoprotein level of 2.22 ug. per cent was found.
The average value for the amount of thyroxine
plus triiodothyronine in these serum samples
was 4.53 yg. per cent. These data may be
compared with results obtained on twenty-five
normal North American control subjects residing temporarily in Washington, D. C.,
who showed an average serum iodoprotein
level of 0.8 ug. per cent and an average Ts +
Ts; level of 3.76 ug. per cent.
The data on urinary iodine are shown in
Table 1 and the average value of 105 yg. per
day is quite similar to values found in the
Eastern United States [9].
The results of studies with Iare shown in
Table mi and are compared with normal val-
ues from the United States; the rate of thyroidal uptake and the rate of urinary excretion
are both decreased. Since they are decreased
more or less proportionately, the calculated
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