QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Finkelstein, J. D. Articles by Harris, B. Search for Related Content PubMed PubMed Citation Articles by Finkelstein, J. D. Articles by Harris, B.

Effect of Nicotinamide on Methionine Metabolism in Rat Liver¹

Veterans Administration Medical Center and George Washington University School of Medicine, Washington, DC 20422

To test the response to increased utilization of methyl groups, we administered large dosages of nicotinamide to rats fed an adequate diet that contained limited amounts of methionine and choline. During the 4 d after the injection, we observed several significant effects on the hepatic concentrations of the enzymes and metabolites of methionine metabolism. Methionine and S-adenosylmethionine remained at control levels; the concentrations of S-adenosylhomocysteine exceeded the control values from 4 to 16 h; and the levels of serine and betaine were lower after 16 h. Treatment with nicotinamide resulted in higher hepatic levels of methionine adenosyltransferase (after 4 h) and cystathionine synthase (after 16 h). These data indicate that increases in both homocysteine methylation and S-adenosylmethionine synthesis may be components of the response to excessive methyl group consumption. An increased synthesis of cystathionine would provide for the removal of S-adenosylhomocysteine (and homocysteine) derived from the adenosylmethionine-dependent methylation of nicotinamide.

KEY WORDS: • methionine • nicotinamide • methyl groups

¹ This research was supported by the Veterans Administration and by Grant No. DK 13048 from the National Institutes of Health.

Manuscript received 25 January 1988. Revision accepted 24 March 1988.

This article has been cited by other articles:

				S.-i. Fukada, M. Setoue, T. Morita, and K. Sugiyama Dietary Eritadenine Suppresses Guanidinoacetic Acid-Induced Hyperhomocysteinemia in Rats J. Nutr., November 1, 2006; 136(11): 2797 - 2802. [Abstract] [Full Text] [PDF]