Serum and Urine CONCENTRATIONS of VITAMIN B12 following Oral Administration of the Vitamin

Abstract

In both normal individual and patients with pernicious anemia in relapse, serum concentrations of vitamin B₁₂ show no significant alteration following the oral administration of 1000 µg. of the vitamin. When the dosage is increased to 5000 µg., serum concentrations in both groups are increased. In pernicious anemia, there is a correlation between hematological response and the demonstration of the vitamin in the serum following oral therapy. Vitamin B₁₂ appears in the serum in combined form after adequate oral dosage. The absence of circulating free vitamin accounts for the failure to detect the increased urinary activity which is observed following parenteral therapy.