Abstract
Iron absorption is a function of the gastro-intestinal mucosal epithelium. The normal non-anemic dog absorbs little iron but chronic anemia due to blood loss brings about considerable absorption—perhaps 5 to 15 times normal. In general the same differences are observed in man (1). Sudden change from normal to severe anemia within 24 hours does not significantly increase iron absorption. As the days pass new hemoglobin is formed. The body iron stores are depleted and within 7 days iron absorption is active, even when the red cell hematocrit is rising. Anoxemia of 50 per cent normal oxygen concentration for 48 hours does not significantly enhance iron absorption. In this respect it resembles acute anemia. Ordinary doses of iron given 1 to 6 hours before radio-iron will cause some "mucosa block"—that is an intake of radio-iron less than anticipated. Many variables which modify peristalsis come into this reaction. Iron given by vein some days before the dose of radio-iron does not appear to inhibit iron absorption. Plasma radio-iron absorption curves vary greatly. The curves may show sharp peaks in 1 to 2 hours when the iron is given in an empty stomach but after 6 hours when the radio-iron is given with food. Duration time of curves also varies widely, the plasma iron returning to normal in 6 to 12 hours. Gastric, duodenal, or jejunal pouches all show very active absorption of iron. The plasma concentration peak may reach a maximum before the solution of iron is removed from the gastric pouch—another example of "mucosa block." Absorption and distribution of radio-iron in the body of growing pups give very suggestive experimental data. The spleen, heart, upper gastro-intestinal tract, marrow, and pancreas show more radio-iron than was expected. The term "physiological saturation" with iron may be applied to the gastro-intestinal mucosal epithelium and explain one phase of acceptance or refusal of ingested iron. Desaturation is a matter of days not hours, whereas saturation may take place within 1 to 2 hours. We believe this change is a part of the complex protein metabolism of the cell.
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Selected References
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- Balfour W. M., Hahn P. F., Bale W. F., Pommerenke W. T., Whipple G. H. RADIOACTIVE IRON ABSORPTION IN CLINICAL CONDITIONS: NORMAL, PREGNANCY, ANEMIA, AND HEMOCHROMATOSIS. J Exp Med. 1942 Jul 1;76(1):15–30. doi: 10.1084/jem.76.1.15. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bogniard R. P., Whipple G. H. V. THE IRON CONTENT OF BLOOD FREE TISSUES AND VISCERA : VARIATIONS DUE TO DIET, ANEMIA AND HEMOGLOBIN INJECTIONS. J Exp Med. 1932 Mar 31;55(4):653–665. doi: 10.1084/jem.55.4.653. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Granick S., Michaelis L. FERRITIN AND APOFERRITIN. Science. 1942 Apr 24;95(2469):439–440. doi: 10.1126/science.95.2469.439. [DOI] [PubMed] [Google Scholar]
- Hahn P. F., Bale W. F., Lawrence E. O., Whipple G. H. RADIOACTIVE IRON AND ITS METABOLISM IN ANEMIA : ITS ABSORPTION, TRANSPORTATION, AND UTILIZATION. J Exp Med. 1939 Apr 30;69(5):739–753. doi: 10.1084/jem.69.5.739. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hahn P. F., Ross J. F., Bale W. F., Balfour W. M., Whipple G. H. RED CELL AND PLASMA VOLUMES (CIRCULATING AND TOTAL) AS DETERMINED BY RADIO IRON AND BY DYE. J Exp Med. 1942 Jan 31;75(2):221–232. doi: 10.1084/jem.75.2.221. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hahn P. F., Ross J. F., Bale W. F., Whipple G. H. THE UTILIZATION OF IRON AND THE RAPIDITY OF HEMOGLOBIN FORMATION IN ANEMIA DUE TO BLOOD LOSS. J Exp Med. 1940 May 31;71(6):731–736. doi: 10.1084/jem.71.6.731. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moore C. V., Arrowsmith W. R., Welch J., Minnich V. STUDIES IN IRON TRANSPORTATION AND METABOLISM. IV. OBSERVATIONS ON THE ABSORPTION OF IRON FROM THE GASTRO-INTESTINAL TRACT. J Clin Invest. 1939 Sep;18(5):553–580. doi: 10.1172/JCI101069. [DOI] [PMC free article] [PubMed] [Google Scholar]