METABOLIC STUDIES WITH STRONTIUM-90
THE SHORTER-TERM BIOLOGICAL HAZARDS OF A FALLOUT FIELD
and water (in the same proportions as are
present in whole milk); and the usual supple-
Samples with very low levels of activity,
such as blood and milk from injected animals
and bones and excreta from infants, were sent
to Nuclear Seience and Engineering Cor-
poration, Pitisburgh, Pennsylvania, for assay.
Bones and excreta from injected animals and
those on the feeding program were assayed
according to the following procedure: After
dry ashing, the samples were digested with
concentrated HNO,or agua regia until solution
was nearly complete and then evaporated to
‘
A
© -ROSY, pragnont fanole
PAT, young adult «
®
oy,
&~TONY, adult mate
@-STUPE, «©
+
i
\
dryness. Dilute HNO, was added so that 10
ml of the final solution represented approxi-
at least 30 days to allow for attainment of
radioactive equilibrium. The Ca“ and Sr®
beta-particle activities were measured with a
cause of the wide variations in the curve shapes
filtration. Aliquots of samples containing only
Sr® were placed in weighed porcelain ashing
capsules, evaporated to dryness, and counted
with a G-M counter. In each case the appro-
has two components with half times of 0.8
priate corrections were made for self-absorp-
tion, and corrected counts were compared with
an aliquot of the administered dose.
RESULTS
Distribution and Excretion of Intravenouslyadministered Sr
The decline in urinary excretion rate of
intravenously administered Sr® is shown in
Figure 2 for four adult rhesus monkeys.
Be-
¢ The reguiar diet contalns 1,395 tg of calcium per day and the low-
salolum clot, 69 mg caleluin per day.
specios (15, 23, 24]. Figure 4 shows the fecal
excretion rate of Sr® in the two surviving adults
to 900 days postinjection. The slope of the
slowest component, which appears at about
200 days, was similar for the two animals despite
It is quite un-
DAYS AFTER INJECTION
to
FECAL EXCRETION OF SR-90
BY ADULT RHESUS MONKEYS
for the various bones. The mean Sr:Ca ratio
for the entire skeleton of this animal was 0.52.
The body burdensof Sr in the two surviving
adults, estimated from bone biopsy, are shown
in Table IL.
Average half times for Sr® were
ealeulated for the male and female, based on
retention 10 days after injection (57.7 percent
and 36.3 percent of the administered dose
respectively), and on the estimated body
burdens at approximately 600 days. For the
male the average half time was 470 days, and
for the female, 315 days. The successive
pregnancies of the female (but without lactation) appeared to hasten the elimination of Sr™.
A measurable amount of Sr®, 1,540.5 dpm,’
was found in a 63.8-mg sample of vertebral
ash obtained in
animal that had
does not seem
because a great
August 1955 from Alice, an
not been given Sr®. This Sr”
to be due to contamination,
deal of care was exercised to
avoid contamination during the operative and
ashing procedures.
DAYS AFTER INJECTION
Ficore 4.~—Feral excretion rate of Srby adulf rhesus
monkeys.
the fact that the female had experienced three
elosely spaced pregnancies.
biopsy.
With the exception of scapulac, paw bones,
andribs, the Sr™:Ca® ratios were quite similar
z
apparently more efficient than that of Ca*.
Similar results have been obtained for other
These differences were
that caudal vericbrae were selected for bone
2
and 4.2 days.
A comparison of the cumulative urinary excretion of Ca* and Sr” is shown in Figure 3 for
two of the adults. In contrast to the wide
variation in the individual rate curves, the
cumulative curves are quite similar for these
two animals. Renal excretion of Sr® was
various paris of the skeletons of an adult. and
an adolescent monkey. The ratios Sr®:Ca‘®
for the skeletal parts are shown for the adult,
As might be expected on the basis of age,
differences in diet, and postinjection interval,
the Sr® Jevel was generally higher in the bones
of the adolescent.
3
thin-end-window G-M counter by differential
og
for the individual animals, a scatter diagram
with an average curve (broken line) is shown.
The average urinary excretion curve (broken)
nated bycither routeis derived from the same
more striking in flat bones than in the long
bones. The Sr® content of the vertebrae
secins to be reasonably representative of the
skeleton as a whole. It was for this reason, as
well as the simplicity of the operative procedure,
Ficure 3.—Cumulative urenary ereretion of Ca® and
Sr? by adult rhesus monkeys.
PER CENT DOSE PER Dar
All samples were stored for
Figure 2.-~Urinary ercretion rate of Srby adult rehesus
monkeys.
ROSY, @-Ca-45, O- Sr-90
TONY, av =, Ans
2
previously [22}.
ol
DAYS AFTER INJECTION
likely that the urinary excretion-rate curve has
a different shape, inasmuch as the Sr” elimi-
Table I shows the distribution of Sr in the
i
mately 0.5 g of ash. Small aliquots were
taken from samples containing both Caand
Sr™, transferred to weighed gold plates, and
treated according to a procedure described
177
source, namely, the circulating blood. Experiments are under way to test this point.
g
1
‘
PER CENT DOSE PER DAY
Radioactive Assay Procedures
CUMULATIVE EXCRETION, PER CENT ADMINSTERED DOSE
e
8
s
5
3
animals were placed on a low-calcium diet ¢
consisting of fruit and vegetables; a milk
substitute of butter, sugar, hydrolyzed casein
ment of vitamins andiron.
URINARY EXCRETION OF GA-45 AND SR-S0
or BY THE ADULT RHESUS MONKEY
URINARY EXCRETION OF INTRAVENOUSLY
ADMINISTERED SR-90 BY ADULT MONKEYS
2
176
|
Tt Martell reports that. the error Jn measurement of Sr® by the “Chicaro
Sunshine Method” used by Nuclear Science Engineering Corporation
is less than £0 pereent (25),
their limits of sensitivity,
‘Theactivity of this sample was well within