Studies on intrinsic factor and pernicious anemia. I. Oral uptake of vitamin B12 in pernicious anemia with increasing doses of an intrinsic factor concentrate
Berlin, H.; Berlin, R.; Brante, G.; Sjoberg, S.G.
Scandinavian Journal of Clinical and Laboratory Investigation 10(3): 278-282
ISSN/ISBN: 0036-5513 PMID: 13602698 Accession: 014204358
Patients with well established pernicious anaemia received, fasting, 1 micro g. vitamin B12 labelled with 0.25 micro C. 60Co by mouth and 2 hr. later 1000 micro g. unlabelled vitamin B12by intramuscular injection. Urine was collected for 24 or 48 hr. for estimation of excreted 60Co and a second injection of unlabelled vitamin was made at 24 hr. After the tests with vitamin alone, and an interval of at least 3 days, the tests were repeated with different amounts of the intrinsic factor preparation suspended with the labelled vitamin. Significant increases in uptake of labelled vitamin were obtained with doses of the intrinsic factor preparation with a vitamin-B12-binding capacity of 500 coli units or more. The response increased most sharply with doses of 1000 to 3000 coli units, but the maximum was attained with 10, 000 or more. The response to 10, 000 coli units was usually, though not invariably, equal to that in normal subjects given the vitamin alone. Responses were too variable to justify the construction of a standard " average response " curve. D. Duncan.