Submitted to: Society of Toxicology
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 1996
Publication Date: N/A
Technical Abstract: The first strong evidence supporting the essentiality of arsenic for animals became available in the 1970s. Arsenic deprivation caused an increased perinatal mortality in rats, goats, and minipigs and death in some lactating goats, apparently from myocardial abnormalities. Recent studies have suggested that arsenic has a physiological role that affects methyl metabolism through methionine. Consistent effects of arsenic deprivation have been seen in the liver concentration of S- adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH). For example, in female rats fed a diet containing less than 10 ng arsenic/g, the liver concentration of SAM was decreased to 87+/-6 nmol/g compared to control values of 104+/-4 nmol/g (mean+/-SE, p<0.05). Liver SAH was unchanged by arsenic deprivation and the SAM/SAH ratio was slightly, but not significantly, decreased. Controls received the same diet but supplemented with 0.5 ug arsenic (as As2O3)/g. Other research has indicated that alteration of methionine metabolism exacerbates arsenic deprivation. Present studies are designed to ascertain the site of methionine metabolism (transsulfuration or methionine recycling) in which arsenic has its physiological role. The arsenic requirement for growing chicks and rats has been suggested to be around 25 ng/g diet. If arsenic is found to be essential for humans, extrapolation of animal data suggests the requirement of arsenic would be about 12 to 25 ug/day.