The regulatory roles of liver and kidney in cobalamin (vitamin-B₁₂) metabolism in the rat: the uptake and intracellular binding of cobalamin and the activity of the cobalamin-dependent enzymes in response to varying cobalamin supply

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dc.contributor.authorScott, J.S.D.
dc.contributor.authorTreston, A.M.
dc.contributor.authorBowman, E.P.W.
dc.contributor.authorOwens, J.A.
dc.contributor.authorCooksley, W.G.E.
dc.date.issued1984
dc.description.abstractTo examine possible regulatory roles of liver and kidney in cobalamin metabolism, specific activities of the two cobalamin-dependent enzymes, uptake in vivo of cyano [57Co]cobalamin [( 57Co]CNCbl) and the binding of [57Co]Cbl to intracellular proteins were measured in normal, cobalamin-loaded and cobalamin-deficient rats. Cobalamin deficiency and cobalamin loading produced greater changes in cobalamin concentration in the kidney than in the liver. Although cobalamin deficiency resulted in a decrease in total methylmalonyl-coenzyme A mutase (methylmalonyl-CoA mutase) in both organs, cobalamin loading had no effect. Neither deficiency nor loading altered total methyltransferase activity. The holoenzyme activities of both enzymes correlated with changes in tissue cobalamin levels. Uptake of [57Co]Cbl indicated that the kidney, in contrast to the liver, increased its uptake during loading and reduced it during deficiency, suggesting a possible regulatory role for this organ. In the normal rat, 24 h after injection of [57Co]CNCbl, 0.3% of the administered [57Co]Cbl was present in the liver as free cobalamin. By contrast, in the kidney, over 13% of the [57Co]Cbl was present in the free form. During deficiency free renal [57Co]Cbl was reduced to 0.6% of the administered [57Co]Cbl whereas in cobalamin-loaded rats it was increased to more than 27%. It is concluded that alterations in tissue cobalamin levels resulting from differences in cobalamin supply are due to changes in the large pool of free cobalamin present in the kidney and not to changes in the intracellular binding.
dc.description.statementofresponsibilityJ. S. D. Scott, A. M. Treston, E. P. W. Bowman, J. A. Owens and W. G. E. Cooksley
dc.identifier.citationClinical Science, 1984; 67(3):299-306
dc.identifier.doi10.1042/cs0670299
dc.identifier.issn1470-8736
dc.identifier.issn1470-8736
dc.identifier.orcidOwens, J.A. [0000-0002-7498-1353]
dc.identifier.urihttp://hdl.handle.net/2440/92986
dc.language.isoen
dc.publisherPortland Press
dc.rights© 1984 The Biochemical Society and the Medical Research Society
dc.source.urihttps://doi.org/10.1042/cs0670299
dc.subjectAnimals
dc.subjectRats, Inbred Strains
dc.subjectRats
dc.subjectLiver
dc.subjectKidney
dc.subjectVitamin B 12 Deficiency
dc.subjectCobalt Radioisotopes
dc.subjectVitamin B 12
dc.subjectTranscobalamins
dc.subjectMethyltransferases
dc.subjectMethylmalonyl-CoA Mutase
dc.subjectChromatography, Gel
dc.subjectGastrectomy
dc.subjectMale
dc.titleThe regulatory roles of liver and kidney in cobalamin (vitamin-B₁₂) metabolism in the rat: the uptake and intracellular binding of cobalamin and the activity of the cobalamin-dependent enzymes in response to varying cobalamin supply
dc.title.alternativeThe regulatory roles of liver and kidney in cobalamin (vitamin-B(12)) metabolism in the rat: the uptake and intracellular binding of cobalamin and the activity of the cobalamin-dependent enzymes in response to varying cobalamin supply
dc.typeJournal article
pubs.publication-statusPublished

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