Liver microsomal mixed-function oxidases in response to polyunsaturated/saturated and n-6/n-3 fatty acid ratios of dietary lipids in rats.
The effects of various polyunsaturated/saturated (P/S; 0.29-2.74) and n-6/n-3 (0.49-11.21) ratios of dietary fatty acids and of phenobarbital (PB) stimulation on the activity of liver microsomal mixed-function oxidase (MFO) system were studied in rats using a combination of palm oil, safflower oil and fish oil concentrate. When the n-6/n-3 ratio was kept constant (4.6-4.9) without induction by PB, the highest P/S ratio (2.74) tended to increase the basal PB-uninduced MFO activities; while the PB-induced MFO activities were elevated as the dietary P/S ratio increased. This definitely indicates the role of both n-6 and n-3 polyunsaturated fatty acids (PUFAs) in the elevation of MFO activities with and without PB stimulation. Whereas the n-6/n-3 ratio was varied while maintaining a constant P/S ratio (1.3), the PB-induced MFO activities were significantly elevated by decreasing the n-6/n-3 ratio although the MFO activities were not affected without PB stimulation. The MFO activities induced by PB were directly related to the n-3 PUFA content and inversely related to the n-6 PUFA content of the diets with n-6/n-3 ratios less than 4.55. These results obtained herein suggest that there are significant differences in the effects of n-6 and n-3 PUFAs on liver microsomal MFO activities, especially in relation to the induction of MFOs by PB.
Saito
M
M
Division of Food Science, National Institute of Health and Nutrition, Tokyo, Japan.
Yamaguchi
M
M
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004032:Diet; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D015118:Eicosapentaenoic Acid / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D005227:Fatty Acids / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D005395:Fish Oils / Q000494:pharmacology; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000096:biosynthesis / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology; D010938:Plant Oils / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D005395:Fish Oils; D010938:Plant Oils; D003577:Cytochrome P-450 Enzyme System; D015118:Eicosapentaenoic Acid; D006899:Mixed Function Oxygenases; D010634:Phenobarbital