{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T02:24:01Z","timestamp":1771640641229,"version":"3.50.1"},"reference-count":20,"publisher":"BMJ","issue":"8","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gut"],"published-print":{"date-parts":[[1981,8]]},"abstract":"<jats:p>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.<\/jats:p>","DOI":"10.1136\/gut.22.8.617","type":"journal-article","created":{"date-parts":[[2007,9,18]],"date-time":"2007-09-18T17:41:31Z","timestamp":1190137291000},"page":"617-622","source":"Crossref","is-referenced-by-count":15,"title":["Subcellular localisation of vitamin B12 during absorption in the guinea-pig ileum."],"prefix":"10.1136","volume":"22","author":[{"given":"W J","family":"Jenkins","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"R","family":"Empson","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"D P","family":"Jewell","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"K B","family":"Taylor","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[1981,8,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1215","DOI":"10.1172\/JCI105615","article-title":"Intrinsic factor mediated attachment of vitamin BI2 to brush borders and microvillous membranes of hamster intestine","volume":"46","author":"Donaldson, R.M.; MacKenzie, I.L.; Trier, J.S.","year":"1967","unstructured":"Donaldson RM, MacKenzie IL, Trier JS. Intrinsic factor mediated attachment of vitamin BI2 to brush borders and microvillous membranes of hamster intestine, J Clin Invest 1967; 46:1215-28.","journal-title":"J Clin Invest"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1111\/j.1365-2141.1957.tb05794.x","article-title":"The site of absorption and tissue distribution of orally administered '06Co-labelled vitamin B12 in the rat","volume":"3","author":"Booth, C.C.; Chanarin, I.; Anderson, B.B.; Mollin, D.L.","year":"1957","unstructured":"Booth CC, Chanarin I, Anderson BB, Mollin DL. The site of absorption and tissue distribution of orally administered '06Co-labelled vitamin B12 in the rat. Br J Haematol 1957; 3:253-61.","journal-title":"Br J Haematol"},{"key":"ref_3","first-page":"663","article-title":"The site of absorption of vitamin B, in the rat","volume":"16","author":"Reynell, P.C.; Spray, G.H.; Taylor, K.B.","year":"1957","unstructured":"Reynell PC, Spray GH, Taylor KB. 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