[Peculiar features of the effect of cobalamines on the metabolism of vitamin B 12 and pantothenic acid in B 12 deficiency].

A single parenteral administration to B12-deficient rats of cyan cobalamine (CN-Cbl), oxycobalamine (OH-Cbl), methyl cobalamine (CH3-Cbl) and adenosyl cobalamine (Ado-Cbl) at a dose of 100 microgram/kg body weight increased the lowered level of total cobalamines in the liver to reach or exceed the norm. The study of cobalamine-protein complexes (CPC) in the liver of B12-deficient rats showed that the content of free cobalamines and CPC was decreased, the level of CPC degrading at 80 degrees C being particularly low. An administration of OH-Cbl and CH3-Cbl raised significantly the content of CPC degrading at 80 degrees C and presumably containing Ado-Cbl. Under the influence of cobalamines the increased activity of alpha-ketoglutarate dehydrogenase in hepatocytes returned to the normal and the CoA level declined only after administration of CN-Cbl and CH3-Cbl.