Hematologic Responses and Concenrtation of Vitamin B12 in Serum and Urine following Oral Administration of

T LIE ABSORPTIOX from the imnt.cstinal tract of small doses of n-itaminn B,2 is impaired inn paticnnts with pernicious anemia. Small doses such as 5 g. gin-cnn daily by mouth produce little or rio hematologic respomise, unnless gin-cnn ssit.in a source of inntrinisic factor ’- 2; larger oral doses arc frequenntly effectin-e es-en if gin-cnn without intrinsic factor. lois-ever, paticnnts appear to n-ary is-idely inn their ’ ability to absorb the vitamin. For instance, daily doses of as little as 25 g. of nitaminn B12 are reported to have produced ann optimal hematologic re-sponnsc inn a patient with pernicious anemia2; on the other hand daily doses of as mucin as 250 g. of vitamin B,2 has-c beenn ineffectin-e inn some patiemits.3 Very large doses arc much more regularly effective, excellent. clinical amid hematologic rcspomnses being reported by Urnglcy4 inn patienits gin-cnn simigle oral doses of 3000 Mg. of the n-itaminn. Though in a few- patiennts the response ivas equin-alenit to that. produced by ann inntramuscular injection of 160.sg. of B,2 or more, the an-erage hematologic rcsponnse is-as equin-alennt t.o that produced by intramuscular injec-tions of about 20 to 40 g. of vitamirn B,2 suggesting that. this is-as tine as-crag