BETAINE EFFECTS ON HEPATIC METHIONINE METABOLISM ELICITED BY SHORT-TERM ETHANOL FEEDING

Previous studies in this laboratory have shown that feeding of ethanol to rats produces prompt inhibition of methionine synthetase (MS) as w ell as a subsequent increase in activity of betaine homocysteine methy ltransferase (BHMT). Further studies have shown that supplemental diet ary betaine enhanced methionine metabolism and S-adenosylmethionine (S AM) generation in control and ethanol-fed rats. Because MS and BHMT ar e both involved in the formation of SAM, this study was conducted to d etermine early effects of ethanol on hepatic SAM levels and the influe nce of betaine supplementation on parameters of methionine metabolism during the early periods of MS inhibition and enhanced BHMT activity. Results showed that ethanol feeding produced a significant loss in SAM in the first week with a return to normal SAM levels in the second we ek. Betaine feeding enhanced hepatic betaine pools in control as well as ethanol-fed animals. This feeding attenuated the early loss of SAM in ethanol-fed animals, produced an early increase in BHMT activity, a nd generated increased levels of SAM in both control and ethanol-fed g roups. Furthermore, betaine lowered significantly the accumulation of hepatic triglyceride produced by ethanol after 2 weeks of ingestion.