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United States Department of Agriculture

Agricultural Research Service

Title: Selenium Status Affects Arsenic Deprivation in Rats

Authors
item Uthus, Eric
item Gao, Junquan - INST FOOD NUTR HYG, CHINA
item Finley, John
item Davis, Cindy
item Nielsen, Forrest

Submitted to: International Symposium on Metal Ions in Biology and Medicine
Publication Type: Proceedings
Publication Acceptance Date: May 7, 2000
Publication Date: May 31, 2000
Citation: Uthus, E.O., Gao, J., Finley, J.W., Davis, C.D., Nielsen, F.H. 2000. Selenium status affects arsenic deprivation in rats. Proceedings of the International Symposium on Metal Ions in Biology and Medicine, San Juan, Puerto Rico, May 7-10, 2002. 6:254-256.

Interpretive Summary: Since 1938 it has been recognized that arsenic (As) and selenium (Se) can affect the metabolism of each other. Furthermore, there is evidence that As and Se can substitute for each other to prevent signs of deficiency. Thus, two experiments that used the rat model were performed to ascertain whether high or low dietary As would enhance the signs of Se deficiency and whether high or low dietary Se would enhance the signs of As deficiency. Findings from experiment 1 indicate that although high dietary As (5 ug As/g diet) does not exacerbate signs of Se deficiency, both low and high dietary Se alter the response of rats fed a diet marginally deficient in As. Results from experiment 2 show that a marginal Se deficiency alters the response of rats fed a diet deficient in As. Also, Se at adequate or excess intake can affect the response of rats to As deprivation. These results suggest that As may be important in Se metabolism and vice versa. These studies also showed that Se deprivation results in a marked decrease in the concentration of plasma total homocysteine as well as results in hypomethylation of DNA. Because hypomethylation of DNA has been associated with increased cancer, this finding may explain some of the reported protective effects of Se on cancer - that is, Se helps prevent hypomethylation of DNA.

Technical Abstract: Since 1938 it has been recognized that arsenic (As) and selenium (Se) can affect the metabolism of each other. Furthermore, there is evidence that As and Se can substitute for each other to prevent signs of deficiency. Thus, two experiments were performed to ascertain whether high or low dietary As would enhance the signs of Se deficiency and whether high or low dietary Se would enhance the signs of As deficiency. In experiment 1, male Fisher-344 rats were fed a torula yeast-sucrose based diet containing 3.9 ng of Se and 85 ng of As per g. In experiment 2, female Sprague Dawley rats were fed a casein-sucrose based diet containing 39 ng of Se and 3.1 ng of As per g diet. Each experiment was factorially arranged. In experiment 1, the dietary variables were supplements of 0, 0.1 and 2.0 ug Se/g diet as selenite or selenomethionine (SeMeth) and 0 and 5 ug As/g diet as arsenite. In experiment 2, the dietary variables were supplements of 0, 0.25 and 2.5 ug Se/g diet as selenite and 0 and 0.25 ug As/g diet as arsenite. Findings from experiment 1 indicate that although high dietary As (5 ug As/g diet) does not exacerbate signs of Se deficiency, both low and high dietary Se alter the response of rats fed a diet marginally deficient in As. Results from experiment 2 show that a marginal Se deficiency alters the response of rats fed a diet deficient in As. Also, Se at adequate or excess intake can affect the response of rats to As deprivation. It was also found that Se deprivation results in a marked decrease in the concentration of plasma total homocysteine in addition to hypomethylation of DNA.

Last Modified: 10/22/2014
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