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Subcellular localisation of vitamin B12 during absorption in the guinea-pig ileum.
Gut. 1981 Aug; 22(8):617-22.Gut

Abstract

The subcellular distribution of vitamin B12 was studied during its absorption in the guinea-pig ileum. Animals were fed either (57Co) or (58Co) cyanocobalamin and killed two or four hours later. At two hours labelled cyanocobalamin was concentrated in brush border and lysosomal fractions of ileal homogenates, with some remaining in the sample layer. In contrast, at four hours labelled cyanocobalamin was concentrated predominantly in the cytosol with much smaller peaks in the brush border and lysosomal fractions. These findings are consistent with vitamin B12 absorption by receptor-mediated endocytosis. It is suggested that, after binding at the brush border, vitamin B12 is first sequestrated within lysosomes, and then released into the cytosol, from where it leaves the cell to enter the portal blood.

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Authors

Jenkins WJ
No affiliation info available
Empson R
No affiliation info available
Jewell DP
No affiliation info available
Taylor KB
No affiliation info available

MeSH

AnimalsCobalt RadioisotopesFemaleGuinea PigsIleumIntestinal AbsorptionSubcellular FractionsTime FactorsVitamin B 12

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

7286777

Citation

Jenkins, W J., et al. "Subcellular Localisation of Vitamin B12 During Absorption in the Guinea-pig Ileum." Gut, vol. 22, no. 8, 1981, pp. 617-22.
Jenkins WJ, Empson R, Jewell DP, et al. Subcellular localisation of vitamin B12 during absorption in the guinea-pig ileum. Gut. 1981;22(8):617-22.
Jenkins, W. J., Empson, R., Jewell, D. P., & Taylor, K. B. (1981). Subcellular localisation of vitamin B12 during absorption in the guinea-pig ileum. Gut, 22(8), 617-22.
Jenkins WJ, et al. Subcellular Localisation of Vitamin B12 During Absorption in the Guinea-pig Ileum. Gut. 1981;22(8):617-22. PubMed PMID: 7286777.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Subcellular localisation of vitamin B12 during absorption in the guinea-pig ileum. AU - Jenkins,W J, AU - Empson,R, AU - Jewell,D P, AU - Taylor,K B, PY - 1981/8/1/pubmed PY - 1981/8/1/medline PY - 1981/8/1/entrez SP - 617 EP - 22 JF - Gut JO - Gut VL - 22 IS - 8 N2 - The subcellular distribution of vitamin B12 was studied during its absorption in the guinea-pig ileum. Animals were fed either (57Co) or (58Co) cyanocobalamin and killed two or four hours later. At two hours labelled cyanocobalamin was concentrated in brush border and lysosomal fractions of ileal homogenates, with some remaining in the sample layer. In contrast, at four hours labelled cyanocobalamin was concentrated predominantly in the cytosol with much smaller peaks in the brush border and lysosomal fractions. These findings are consistent with vitamin B12 absorption by receptor-mediated endocytosis. It is suggested that, after binding at the brush border, vitamin B12 is first sequestrated within lysosomes, and then released into the cytosol, from where it leaves the cell to enter the portal blood. SN - 0017-5749 UR - https://www.unboundmedicine.com/medline/citation/7286777/Subcellular_localisation_of_vitamin_B12_during_absorption_in_the_guinea_pig_ileum_ L2 - https://gut.bmj.com/lookup/pmidlookup?view=long&pmid=7286777 DB - PRIME DP - Unbound Medicine ER -