In the absorption of Hb iron (HbFe), heme is separated from globin in the intestinal lumen and enters mucosal cells where Fe is split off and transported to blood. Previous studies indicated that this final step is the limiting one in absorption of HbFe in normal and Fe loaded animals but not in Fe-deficient animals. The present studies were designed to determine the limiting step in absorption of HbFe in Fe-deficient dogs. Varying Amounts of 59Fe labeled Hb were injected into closed duodenal loops in anesthetized dogs. Each step in the absorptive process was measured: intralumenal separation of the heme from Hb; mucosal uptake of heme; intramucosal splitting of Fe from heme; transport of Fe to blood. This process was characterized using a five compartment kinetic model. The resulting seven rate constants were determined to best describe the observed absorption data. Results show: 1) with increasing dose of 59HbFe, mucosal uptake of heme, Fe split from heme in mucosa, and Fe transported to blood all increase linearly. 2) Mucosal 59Fe-heme accumulates over the 3-hour period while 59Fe does not, indicating rapid transport of 59Fe split from heme. These results suggest that the rate limiting step in absorption of HbFe in Fe-deficient dogs is the splitting of Fe from heme in the mucosa.
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http://dx.doi.org/10.1093/ajcn/34.9.1686 | DOI Listing |
Biochim Biophys Acta Mol Cell Res
January 2023
Jagiellonian University, Jagiellonian Centre for Experimental Therapeutics (JCET), 14 Bobrzyńskiego Str., 30-348 Krakow, Poland. Electronic address:
Sulfhemoglobinemia is an incurable disease caused by an overdose of sulfur-containing drugs with oxidizing properties. Its diagnosis remains hindered due to the similarity of symptoms to other pathological state - methemoglobinemia, as well as contradictory information on the structure and characteristics of sulfhemoglobin. Herein, we present sulfhemoglobinemia model on living functional human erythrocytes, designed to recreate processes which could take place in a patient body in order to complement missing information and highlight distinctiveness of two hemoglobin (Hb) adducts formed after interaction with sulfur donors.
View Article and Find Full Text PDFNutrients
August 2019
USDA-ARS, Robert W. Holley Center for Agriculture and Health, Cornell University, Ithaca, NY 14853, USA.
The common dry bean ( L.) is a globally produced pulse crop and an important source of micronutrients for millions of people across Latin America and Africa. Many of the preferred black and red seed types in these regions have seed coat polyphenols that inhibit the absorption of iron.
View Article and Find Full Text PDFFree Radic Biol Med
December 2016
Institute of Chemistry, The Accelerator Laboratory, the Hebrew University of Jerusalem, Jerusalem 91904, Israel. Electronic address:
Stable nitroxide radicals have multiple biological effects, although the mechanisms underlying them are not fully understood. Their protective effect against oxidative damage has been mainly attributed to scavenging deleterious radicals, oxidizing reduced metal ions and reducing oxyferryl centers of heme proteins. Yet, the potential of nitroxides to protect heme proteins against inactivation while suppressing or enhancing their catalytic activities has been largely overlooked.
View Article and Find Full Text PDFNutr J
January 2015
USDA/ARS, Robert W, Holley Center for Agriculture and Health, Cornell University, Ithaca, NY 14853, USA.
Background: Our objective was to compare the capacity of iron (Fe) biofortified and standard pearl millet (Pennisetum glaucum L.) to deliver Fe for hemoglobin (Hb)-synthesis. Pearl millet (PM) is common in West-Africa and India, and is well adapted to growing areas characterized by drought, low-soil fertility, and high-temperature.
View Article and Find Full Text PDFNutr J
January 2013
USDA-ARS Robert W, Holley Center for Agriculture and Health, 538 Tower Road, Cornell University, Ithaca, NY 14853, USA.
Background: Iron (Fe) deficiency is the most common micronutrient deficiency worldwide. Iron biofortification is a preventative strategy that alleviates Fe deficiency by improving the amount of absorbable Fe in crops. In the present study, we used an in vitro digestion/Caco 2 cell culture model as the guiding tool for breeding and development of two maize (Zea mays L.
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