Effects of Dietary α-Linolenic, Eicosapentaenoic and Docosahexaenoic Acids on Hepatic Lipogenesis and β-Oxidation in Rats

Ikuo Ikeda, Jae Young Cha, Teruyoshi Yanagita, Noriaki Nakatani, Kazuhiro Oogami, Katsumi Imaizumi, Kazunaga Yazawa

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108 Citations (Scopus)

Abstract

The effects of dietary α-linolenic, eicosapentaenoic and docosahexaenoic acids on the enzyme activities related to hepatic lipogenesis and β-oxidation were compared under constant polyunsaturated/monounsaturated/saturated fatty acids and n-6/n-3 ratios of dietary fats in rats. Dietary fat containing linoleic acid as the sole polyunsaturated fatty acid (PUFA) was also given as a control. The concentration of serum triglyceride and phospholipid in the three n-3 PUFA groups was lower than in the linoleic acid group. The hepatic triglyceride concentration was lower and the phospholipid concentration was higher in the three n-3 PUFA groups than in the linoleic acid group. Cytosolic fatty acid synthase (FAS) activity was lower in the n-3 PUFA groups than in the linoleic acid group, the reduction being more predominant in the eicosapentaenoic acid and docosahexaenoic acid groups than in the α-linolenic acid group. The cytosolic activities of the NADPH-generating enzymes, glucose-6-phosphate dehydrogenase (G6PDH) and the malic enzyme, were lower in the three n-3 PUFA groups. The activity of carnitine palmitoyltransferase (CPT) in mitochondria was higher only in the eicosapentaenoic acid group than in the other groups. The activity of Mg2+-dependent phosphatidate phosphohydrolase (PAP) in microsomes and cytosol was lower in the eicosapentaenoic and docosahexaenoic acid groups than in the linoleic acid group, while there was no effect of dietary fats on the activities of diacylglycerol acyltransferase (DGAT) and glycerol-3-phosphate acyltransferase (G3PAT) in microsomes. The CTP: phosphocholine cytidylyltransferase (CT) activity in the homogenate was lower in the n-3 PUFA groups, the reduction being more prominent in the eicosapentaenoic and docosahexaenoic acid groups than in the α-linolenic acid group. The choline kinase (CK) activity in cytosol was lower in the eicosapentaenoic acid group than in the linoleic acid group. These results showed that dietary α-linolenic, eicosapentaenoic and docosahexaenoic acids differently influenced hepatic lipogenesis and the partition of fatty acid into oxidation or glycerolipid synthesis.

Original languageEnglish
Pages (from-to)675-680
Number of pages6
JournalBioscience, Biotechnology and Biochemistry
Volume62
Issue number4
Publication statusPublished - 1998 Apr
Externally publishedYes

Keywords

  • α-linolenic acid
  • β-oxidation
  • Docosahexaenoic acid
  • Eicosapentaenoic acid
  • Lipogenesis

ASJC Scopus subject areas

  • Food Science
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Biotechnology
  • Chemistry (miscellaneous)
  • Applied Microbiology and Biotechnology
  • Bioengineering

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  • Cite this

    Ikeda, I., Cha, J. Y., Yanagita, T., Nakatani, N., Oogami, K., Imaizumi, K., & Yazawa, K. (1998). Effects of Dietary α-Linolenic, Eicosapentaenoic and Docosahexaenoic Acids on Hepatic Lipogenesis and β-Oxidation in Rats. Bioscience, Biotechnology and Biochemistry, 62(4), 675-680.