Blood, 1960, Vol. 15, No. 5, pp. 646-661.
© 1960 American Society of Hematology, Inc.
The Kinetics of Intravenously Injected Radioactive Vitamin
B12: Studies on Normal Subjects and Patients with Chronic
Myelocytic Leukemia and Pernicious Anemia
EUGENE A. BRODY 1,
SOLOMON ESTREN 1, and
LOUIS R. WASSERMAN 1
1 Department of Hematology, The Mount Sinai Hospital, New York, N. Y.
1. Studies of the fate of intravenously injected radioactive vitamin B12
have been performed in patients with normal, low and high serum concentrations of vitamin B12.
2. Abnormal plasma disappearance curves were noted in chronic myelocytic leukemia, pernicious anemia in relapse and in remission, total gastrectomy and malabsorption syndrome.
3. In chronic myelocytic leukemia, the slow clearance of plasma radioactivity may be explained by the increased binding capacity of the plasma
proteins for vitamin B12.
4. Plasma clearance of radioactivity is slower than normal in pernicious
anemia, even in remission. The failure of the disappearance curve to return
to normal in pernicious anemia in complete remission suggests the existence
of a plasma "B12-transferase," whose function is to transfer circulating B12
to the tissues. The disappearance curves suggest that the amount of such
"B12-transferase" is diminished in pernicious anemia, total gastrectomy and
certain Cases of malabsorption syndrome.
5. A relationship between a hypothetical "B12-transferase" and intrinsic
factor is discussed.
