Effect of N,N-Dimethylglycine on Homocysteine Metabolism in Rats Fed Folate-Sufficient and Folate-Deficient Diets

摘要

Objective This study aimed to investigate the effects of N,N-dimethylglycine(DMG) on the concentration and metabolism of plasma homocysteine(pHcy) in folate-sufficient and folate-deficient rats.Methods In this study, 0.1% DMG was supplemented in 20% casein diets that were either folatesufficient(20 C) or folate-deficient(20 CFD). Blood and liver of rats were subjected to assays of Hcy and its metabolites. Hcy and its related metabolite concentrations were determined using a liquid chromatographic system.Results Folate deprivation significantly increased pHcy concentration in rats fed 20 C diet(from 14.19 ±0.39 μmol/L to 28.49 ± 0.50 μmol/L;P < 0.05). When supplemented with DMG, pHcy concentration was significantly decreased(12.23 ± 0.18 μmol/L) in rats fed 20 C diet but significantly increased(31.56 ±0.59 μmol/L) in rats fed 20 CFD. The hepatic methionine synthase activity in the 20 CFD group was significantly lower than that in the 20 C group;enzyme activity was unaffected by DMG supplementation regardless of folate sufficiency. The activity of hepatic cystathionine β-synthase(CBS) in the 20 CFD group was decreased but not in the 20 C group;DMG supplementation enhanced hepatic CBS activity in both groups, in which the effect was significant in the 20 C group but not in the other group.Conclusion DMG supplementation exhibited hypohomocysteinemic effects under folate-sufficient conditions. By contrast, the combination of folate deficiency and DMG supplementation has deleterious effect on pHcy concentration.