Author
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Uthus, Eric |
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Submitted to: Society of Environmental Geochemistry and Health International Conference O
Publication Type: Proceedings Publication Acceptance Date: 9/1/1995 Publication Date: N/A Citation: N/A Interpretive Summary: Arsenic at high concentrations is toxic; more and more evidence in laboratory animals suggests that at low concentrations arsenic may be beneficial. Various studies have attempted to determine the physiological site at which arsenic is important. As of yet, no specific physiological function can be attributed to arsenic. A method that can help determine the site of action of arsenic is mathematical modeling. Using this approach the appearance/disappearance of an easily traceable radioactive arsenic isotope was followed in hamsters. Mathematical equations were derived to define the movement of the isotope throughout various organs. This information can be used to better determine how arsenic is metabolized and will suggest important control points of arsenic metabolism. Knowing these control points will help determine the physiological site of action of arsenic. These studies are important to better understand the metabolism of arsenic and to determine whether or not arsenic has a beneficial role for animal and humans. Technical Abstract: Male, Golden Syrian hamsters were fed a diet containing 0.5 ug As (as As**20**3)/g. After 10 weeks the hamsters were given an oral dose of 73/74**As (5 uCi 73**As, 0.4 uCi 74**As, 0.5 ug arsenite). Whole body retention and fecal excretion of 74**As were followed for 10 days in 5 hamsters by whole body count techniques. Absorption of arsenite was determined to be 66.3+/-5.7%. About 1% of the dose was retained after 5 days. The remaining hamsters were killed at various time points (10 minutes to 15 days) after dosing; organs were counted for 73**As. For all organs, the peak 73**As counts occurred within 30-60 minutes. Liver and muscle accounted for the largest % dose at peak times; brain and spleen the least. Data from this experiment were modeled by using SAAM. Three or more compartments for each organ or group of organs modeled were necessary to approximate the data. The model calculated that liver and blood should contain about 0.2 and 0.1 ug arsenic, respectively; these numbers are close to analyzed values. The model also predicted that the total body arsenic content in hamsters fed this diet is 5.7 ug. Modeling studies provide information on homeostatic mechanisms of arsenic. Thus, these studies will be useful for those who study arsenic at physiologic, pharmacologic, and toxicologic concentrations. |
