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Non‐haem iron transport in the rat proximal colon
Author(s) -
Johnston K. L.,
Johnson D. M.,
Marks J.,
Srai S. K.,
Debnam E. S.,
Sharp P. A.
Publication year - 2006
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.2006.01585.x
Subject(s) - dmt1 , chemistry , transporter , divalent metal , iron deficiency , medicine , in vivo , lumen (anatomy) , large intestine , small intestine , absorption (acoustics) , endocrinology , proximal colon , dietary iron , biochemistry , metal , biology , colorectal cancer , materials science , anemia , gene , organic chemistry , cancer , microbiology and biotechnology , composite material
Background Only 10% of dietary iron is absorbed in the duodenum which implies that 90% (approximately 9 mg day −1 ) reaches the lower small intestine and colon. Therefore the purpose of this study was to assess the iron transport capacity of the rat proximal colon and to determine whether iron absorption is regulated by changes in dietary iron content. Materials and methods Rats were fed for 14 days on either iron adequate (44 mg Fe kg −1 diet) or iron‐deficient (< 0·5 mg Fe kg −1 diet) diets. The 59 Fe transport across the colonic epithelium and its subsequent appearance in the blood were measured in vivo . In separate studies the colon was excised and used to measure divalent metal transporter expression. Results Divalent metal transporter (DMT1) was expressed at the apical membrane of the surface epithelium in rat proximal colon. In animals fed an iron‐deficient diet, DMT1 mRNA and protein expression were increased. This was accompanied by a significant increase in tissue 59 Fe uptake. Conclusions The proximal colon can absorb non‐haem iron from the intestinal lumen. The purpose of this mechanism remains to be elucidated.