1981 Volume 55 Issue 3 Pages 155-161
The changes of forms of cobalamins in human serum and urine following oral and intramuscular administration of CN-B12, OH-B12, DBCC and CH3-B12 were measured by chromatographic microbioassay. The total serum cobalamin levels after a single oral dose of 3,000 /μg of cobalamins reached the maximum of 150〜160 per cent in 3 hours as compared with the respective pre-treatment levels, being due to an increase of the similar forms as cobalamins given orally. As to the excretion of cobalamins in the urine after oral administration of cobalamins, it was found that 1.3〜1.9 μg of the similar forms as cobalamins given orally was excreted in the first 8 hours. When the changes of serum cobalamin levels in human after oral dose of 1,500 μg cobalamins daily were compared among respective cobalamins, no significant differences were observed. After continuous intramuscular administration of cobalamins, serum CN-B_<12> level was low and urinary excretion of CN-B_<12> in-creased in the CN-B_<12>-administered group as compared with other cobalamins -administered groups.
