Structural and cellular adaptation of duodenal iron uptake in rats maintained on an iron-deficient diet
| Autor: | Edward S. Debnam, M. R. Dashwood, Surjit K. S. Srai, M. W. Smith |
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| Rok vydání: | 2000 |
| Předmět: |
Male
medicine.medical_specialty Cellular adaptation Duodenum Physiology Enterocyte Clinical Biochemistry Biology digestive system Rats Sprague-Dawley Physiology (medical) Internal medicine medicine Animals Receptor Iron uptake Anemia Iron-Deficiency Microvilli digestive oral and skin physiology Cell Differentiation Iron deficiency medicine.disease Adaptation Physiological Molecular medicine Small intestine Diet Rats Enterocytes Endocrinology medicine.anatomical_structure Hematocrit Intestinal Absorption Biochemistry Animal Nutritional Physiological Phenomena Iron Dietary |
| Zdroj: | Pflügers Archiv - European Journal of Physiology. 439:449-454 |
| ISSN: | 1432-2013 0031-6768 |
| Popis: | Iron deficiency induced in rats maintained on a commercial diet with a low iron content has been used to investigate adaptive mechanisms that enhance duodenal iron uptake. These adaptive changes have been divided into those that result from changes in villus surface area (structural adaptation) and those that reflect changes in the way individual enterocytes express iron transport function (cellular adaptation). Cellular adaptation was assessed by carrying out microdensitometry of autoradiographs prepared from duodenal tissue previously incubated for 5 min in 200 micromol/l 59Fe2+-ascorbate. Structural adaptation was studied by performing image analysis of microdissected and sectioned villi. Cellular adaptation involved increased iron uptake by enterocytes present in the lower villus. Thus iron deficiency resulted in a threefold enhanced expression of uptake in the lower 100 microm villus (3.9+/-2.4 versus 12.6+/-1.5 arbitrary units, P0.001). Maximal uptake was reached in the upper region of both control and iron-deficient villi, but iron deficiency had no effect on cellular uptake at this part of the villus. Structural adaptation involved the lengthening (+16%, P0.05) and broadening (+14%) of villi in the duodenum of iron-deficient rats. The resultant expansion in villus area caused a further increase in uptake that was mostly expressed in the upper villus. Maximal uptake corrected for structure occurred in the middle third of villi from control and iron-deficient rats. Cellular plus structural adaptation produced a twofold increase in iron uptake. More than half of this effect was caused by changes in villus structure. [3H]Thymidine labelling experiments revealed a slightly earlier expression of enterocyte iron uptake in iron deficiency. |
| Databáze: | OpenAIRE |
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