Blood, 1955, Vol. 10, No. 2, pp. 95-114.
© 1955 American Society of Hematology, Inc.
Surface Scintillation Measurements in Humans of the
Uptake of Parenterally Administered Radioactive Vitamin B12
GEORGE B. JERZY GLASS 1,
LINN J. BOYD 1, and
GERALD A. GELLIN 1
1 Department of Medicine and the Gastroenterology Research Laboratory, New
York Medical College, Flower and Fifth Avenue Hospitals, New York, N. Y.
1. The distribution of radioactive vitamin B12 in humans was studied by scintillation counting of radioactivity over various skin projections of underlying
organs in five individuals, following parenteral administration of radioactive
vitamin B12. The results of these investigations showed that the scintillation surface measurements of the radioactivity following parenteral administration of
radioactive vitamin B12 may be profitably applied to the study of the metabolic
turnover of vitamin B12 under normal and pathological conditions in humans.
2. In two young normal control subjects over 96 per cent of the parenterally
administered radioactive vitamin B12 (5 and 10 µg. containing 0.925 µc. of Co60)
disappeared from the site of the intramuscular injection within three to four
hours, and during that time radioactivity rose to its peak value over the areas
corresponding to kidney, spleen and iliac crest, and somewhat later over the muscles of the extremities. Subsequently, a gradual decline of radioactivity was
observed over the spleen, kidney and extremities, so that at the end of three
months in the normal subject from 
to 
of radioactivity as compared to peak
values was observed over the spleen and left kidney and about 
over the calf
muscle.
The projection areas of the liver differed from all the other areas of the body
in requiring about five to six days to build up the peaks of radioactivity. These
exceeded counts over the kidney and spleen about 2 times, counts over the
iliac crest approximately 7 times, and those over the calves about 17 times. The
decline of radioactivity over the liver and iliac crest was very slow and small.
3. The patterns of the uptake of injected radioactive vitamin B12 by the totally
gastrectomized patient were grossly similar to those observed in normal controls,
except for possibly slightly faster absorption of the injected material from the site
of injection, and somewhat faster and larger accumulation, but also faster discharge of radioactivity from the liver area.
4. In a patient with pernicious anemia in partial remission who received three
parenteral doses of 2 respectively 10 µg. radioactive vitamin B12 (0.185-0.925
µc. Co60), the uptake of the radioactive vitamin B12 by the kidney and spleen area
was slightly higher than that of the normal controls, that of the liver similar to
the normal, and that over the iliac crest showing a significantly faster decline
than in normals during the course of study. The uptake of radioactive vitamin B12
in the same patient following intravenous injection of the same dose of radioactive
vitamin B12 was grossly similar to that following intramuscular injection of the
same dose of radioactive material, except for the faster accumulation of radioactivity over the kidney area.
5. From 65 to 86 per cent of the peak radioactivity persisted over the liver 2-3
months after parenteral administration of radioactive vitamin B12 to two control
subjects. After five months 60 per cent of the initial peak of radioactivity was
still observed over the liver in the patient with anemia of sprue in remission, 85
per cent in a patient with pernicious anemia in partial remission, and at the end
of eight months still 35 per cent of the peak liver count in a patient with total gastrectomy without anemia. This does not take into account the normal decay of
Co60 which is about 1 per cent per month.
6. If the presence of Co60 in the liver indicates the deposition of Co60-B12 in this
organ, which is most probable, then the long storage of vitamin B12 in the liver
may explain the long time needed in humans for depletion of hepatic stores of
vitamin B12, as well as for long remissions observed in pernicious anemia following
parenteral treatment with liver extracts or vitamin B12.
Submitted on May 10, 1954
Accepted on July 21, 1954
