Effect of Vitamin B12 Deficiency on S-Adenosylmethionine Metabolism in Rats

Tadashi Doi, Naoto Tadano, Takeshi Iijima, Akio Maekawa, Tetsunori Kawata

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


The effect of vitamin B12 (B12) deficiency on the levels of S-adenosylmethionine (SAM) in tissues and the activities of hepatic methionine synthase, methionine adenosyltransferase and glycine N-methyltransferase were investigated. The striking depression of methionine synthase activity was observed in all rats fed the B12-deficient diets with or without methionine supplementation for 150 days. The SAM level in liver was decreased by B12 deficiency. However, brain SAM level was not affected. The activities of hepatic methionine adenosyltransferase isozymes, α-form and β-form, were decreased by B12 deficiency. Hepatic glycine N-methyltransferase activity in rats fed the low methionine-B12-deficient diet showed a tendency to lower, although the change the activity was not statistically significant, compared with B12-supplemented rats. It is proposed that the fall in the activity of hepatic methionine adenosyltransferase may be one of the causes of the decreased hepatic SAM level in B12-deficient rats.

Original languageEnglish
Pages (from-to)1-9
Number of pages9
JournalJournal of Nutritional Science and Vitaminology
Issue number1
Publication statusPublished - 1989


  • S-adenosylmethionine
  • glycine N-methyltransferase
  • methionine adenosyltransferase
  • vitamin B-deficient rats

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics


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