Effect of dietary alpha-linolenic, eicosapentaenoic and docosahexaenoic acids on liver microsomal mixed-function oxidases in rats.
This study was undertaken to compare the effects of three major dietary n-3 fatty acids, i.e. alpha-linolenic acid (C18:3, n-3; LN), eicosapentaenoic acid (C20:5, n-3; EPA) and docosahexaenoic acid (C22:6, n-3; DHA), on liver microsomal mixed-function oxidase activities with and without phenobarbital (PB) induction. Male Sprague-Dawley rats were fed a 5% lipid diet containing either LN, EPA or DHA as major constituent fatty acid (about 40%) of dietary lipids for 15 days. The fatty acid compositions of liver microsomal lipids of each n-3 fatty acid group were characteristically different, particularly in the n-3 fatty acid compositions, but were nearly the same with and without PB treatment. Dietary LN, EPA and DHA did not affect the levels of PB-inducible cytochrome P-450 species nor the activities of aminopyrine N-demethylase and aniline hydroxylase. However, the PB-uninduced constitutive levels of cytochromes P-450 increased in the following order with a slight but significant difference between LN and DHA groups: LN group < EPA group < DHA group. Both the PB-uninduced activities of aminopyrine N-demethylase and aniline hydroxylase changed in a very similar manner to the constitutive levels of cytochromes P-450. These results suggest that the uninduced constitutive level of certain cytochrome P-450 species is modulated differentially by dietary LN, EPA and DHA, whereas dietary LN, EPA and DHA do not affect the PB-inducible levels of cytochrome P-450 species.
Saito
M
M
Division of Food Science, National Institute of Health and Nutrition, Tokyo, Japan.
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D015118:Eicosapentaenoic Acid / Q000494:pharmacology*; D004790:Enzyme Induction / Q000187:drug effects; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D006899:Mixed Function Oxygenases / Q000032:analysis / Q000096:biosynthesis / Q000502:physiology*; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017962:alpha-Linolenic Acid / Q000494:pharmacology*
D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D003577:Cytochrome P-450 Enzyme System; D015118:Eicosapentaenoic Acid; D006899:Mixed Function Oxygenases; D010634:Phenobarbital