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Author

Xi Fu

Date of Award

4-14-1999

Document Type

Restricted Thesis: Campus only access

Degree Name

Bachelor of Science

Department

Biology

First Advisor

Dr. Richard Topham

Abstract

Iron homeostasis in mammals is principally maintained by the regulation of intestinal iron absorption and not by excretion. The roles of ferritin, transferrin, and ferrioxidase and ferrireductase activities in the intestinal mucosal cell cytosol were studied to understand the molecular mechanisms by which iron absorption is regulated. Proteins in the intestinal mucosal cell cytosol samples were separated by electrophoresis and the concentrations of ferritin and transferrin in control and iron-deficient rats were compared by Coomassie blue staining. It was shown that there were no noticeable changes in the concentrations of ferritin and transferrin in rats raised on control or iron-deficient diets. Iron-specific staining of ferritin and transferrin showed no changes in the amount of iron incorporated into these two proteins between rats raised on different diets. Enzymic activity assays show that both the ferrireductase and ferroxidase activities are increased in iron-deficient animals. Mucosal cell cytosol proteins were separated by High Performance Liquid Chromatography (HPLC). Graphite furnace atomic absorption spectroscopy (GFAAS) was used to analyze the iron concentration in rabbit mucosal cytosol tissue. Proteins ranging from 300kDa-700kDa increased in iron-deficient animals compared to control animals. Preliminary iron studies on this fraction indicate a decrease in the amount of iron incorporated into ferritin in iron-deficient animals. Substantial amounts of iron were detected in a protein larger than ferritin. Moreover, the iron absorption peak of this protein was shifted to higher molecular weight in iron-deficient animals.

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