ARS | Publication request: DIFFERENTIAL EFFECTS OF DIETARY SELENIUM (SE) AND FOLATE ON METHYL METABOLISM IN LIVER AND COLON OF RATS

Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract
Publication Acceptance Date: December 1, 2004
Publication Date: March 7, 2005
Publisher's URL: http://www.fasebj.org
Citation: Uthus, E.O., Ross, S., Davis, C. 2005. Differential effects of dietary selenium (Se) and folate on methyl metabolism in liver and colon or rats [abstract]. The Federation of American Societies for Experimental Biology Journal. 19(5):A1013.

Technical Abstract: A previous study compared the effect of folate on methyl metabolism in colon and liver of rats fed a Se-deficient diet (<3 ng Se/g) vs a diet containing supranutritional Se (2 µg selenite/g; J Nutr 133: 2907, 2003). The purpose of this study was to investigate the interactive effects of folate and adequate Se (0.2 µg/g) on methyl metabolism in colon and liver. Weanling, Fischer-344 rats (n=6/diet) were fed diets containing 0 or 0.2 µg Se (as selenite)/g and 0 or 2 µg folate/g in a 2 x 2 factorial design. After 70 days, plasma homocysteine was increased (p<0.0001) by folate deficiency; this increase was markedly exacerbated (p<0.0001) in rats fed 0.2 µg Se/g. Colon and liver S-adenosylhomocysteine were highest (p<0.006) in rats fed deficient folate and adequate Se. Although folate deficiency decreased liver S-adenosylmethionine (SAM, p<0.0001), it had no effect on colon SAM. Global DNA methylation was decreased (p<0.04) by Se deficiency in colon but not liver. Se deficiency did not affect DNA methyltransferase activity in liver but tended to decrease (p<0.06) the activity of the enzyme in the colon. These results in rats fed adequate Se are similar to the results found in our earlier study when the rats were fed supranutritional Se. This suggests that the effects on these parameters of methyl metabolism are the result of Se deficiency.