Effect of Vitamin B12-Deficiency on the Activity of Hepatic Cystathionine β-Synthase in Rats

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

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The effect of vitamin B12(B12)-deficiency on the activities of hepatic methionine synthase, homocysteine methyltransferase, and cystathionine β-synthase was investigated in rats. The rats bred from B12-deficient dams were fed the B12-deficient diets for 150 days after weaning. Growth retardation of the B12-deficient rats was already observed on day 30 and continued through 150 days. But dietary supplementation of 0.5% dl-methionine slightly improved the growth retardation. Urinary excretion of methylmalonic acid increased to about 15 mg/mg creatinine and hepatic B12 concentration declined to about 2 ng/g liver after a 150-day feeding of the B12-deficient diets. Hepatic methionine synthase activity in rats fed the B12-deficient diets supplemented with or without methionine decreased to about 5% of B12-supplemented controls. Hepatic betaine-homocysteine methyltransferase activity showed no significant change caused by B12-deficiency. Hepatic cystathionine β-synthase activity in rats fed the B12-deficient diets supplemented with or without methionine decreased to about 61% and 27% of their B12-supplemented controls, respectively, but the decrease was partially improved by methionine supplementation. In conclusion, the rats bred from B12-deficient dams showed a severe B12-deficiency after a 150-day feeding of the B12-deficient diets. The decrease of hepatic cystathionine β-synthase activity was supposed to be due to the adaptation by the defect of methionine resynthesis.

Original languageEnglish
Pages (from-to)101-110
Number of pages10
JournalJournal of Nutritional Science and Vitaminology
Volume35
Issue number2
DOIs
Publication statusPublished - 1989

Keywords

  • betaine-homocysteine methyltransferase
  • cystathionine β-synthase
  • methionine synthase
  • vitamin B-deficient rats

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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