Inhibition of copper absorption by zinc |
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Authors: | Raul A Wapnir Cheryl Balkman |
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Institution: | 1. Department of Pediatrics, North Shore University Hospital-Cornell, University Medical College, 11030, Manhasset, NY
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Abstract: | Copper and zinc interact at the intestinal mucosal level, affecting copper absorption. Amino acids, such as histidine, may
affect the absorption of these two elements by chelating these cations. The two mechanisms could have additive potential.
This possibility was investigated using a duodenal-jejunal single-pass perfusion procedure in anesthetized rats. Copper absorption
and tissue retention from solutions containing 0.1 mM copper were determined in the presence of either no zinc or equimolar zinc, or at a zinc/copper ratio of 10/1, either without
histidine or with histidine at a 10/1 or 20/1 ratio to copper. Copper removal from the intestinal lumen was decreased by zinc,
and further reduced by increasing concentrations of histidine. There was a greater accumulation of copper in the small intestine,
reaching a maximum with a 10-fold excess of histidine. With zinc at a 10/1 ratio to copper, the addition of a 10- or 20-fold
molar excess of histidine further decreased the net uptake of copper from the perfusate while greater copper accumulation
in the tissue occurred. Histidine thus enhances the inhibitory effects of zinc on copper absorp|tion, suggesting the application
of convergent mechanisms for diminishing copper uptake. This could be relevant for the treatment of Wilson’s disease. |
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Keywords: | Index Entries" target="_blank">Index Entries Copper absorption zinc histidine intestinal absorption amino acids |
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