Author
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Uthus, Eric |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 9/22/1997 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Although numerous studies have indicated that arsenic is an essential nutrient, the physiological role for arsenic is open to conjecture. Because it was found that alteration in methionine status or metabolism affected signs of arsenic deprivation and that many of these signs were related to methionine or methyl metabolism, it was hypothesized that arsenic has a physiological role affecting methionine metabolism. Methionine metabolism can be divided into 2 general areas methionine cycling and transsulfuration. In an experiment where the transsulfuration pathway was stressed, arsenic deprivation resulted in, along with other effects, a significant accumulation of calcium in kidneys of female rats. More recently, research has focused on determining the effect of arsenic deprivation on parameters related to methionine cycling. In these studies, arsenic deprivation decreased the specific activity of betaine homocysteine methyltransferase. Perhaps more important, though, is that arsenic deprivation reduced the concentration of S-adenosylmethionine (SAM) and an increased concentration of S-adenosylhomocysteine (SAH) in liver which resulted in a decreased SAM/SAH ratio. Other workers have shown that a decreased SAM/SAH ratio is associated with DNA hypomethylation, and that DNA hypomethylation is associated with some types of cancer. Preliminary evidence suggests that, as a result of arsenic deprivation, the ratio of SAM/SAH is decreased and DNA is undermethylated. Long term studies are planned to ascertain whether or not this would predispose an arsenic deprived-animal to cancer. |
