Influence of dietary fish oil on the relative synthesis of triacylglycerol and phospholipids in rat liver in vivo.
The influence of dietary fish oil containing n-3 polyunsaturated fatty acids on the biosynthesis of triacylglycerol relative to total individual phospholipids was studied in rat liver in vivo. The dietary lipid (10% by weight of diet) was either sunflower oil enriched in linoleic acid (SO group) or MaxEPA fish oil/sunflower oil, 9:1 by weight (FO group) enriched in eicosapentaenoic acid (EPA, 20:5n-3) plus docosahexaenoic acid (DHA, 22:6n-3). After a 3-week feeding period, the triacylglycerol content (in mumol/g liver) was 44% lower in the FO group relative to the SO animals. The in vivo incorporation of [3H]glycerol into individual hepatic lipids resulted in triacylglycerol/total phospholipid radioactivity ratios of 2.1 and 0.9 for the SO and FO groups, respectively. These results indicate an inhibitory effect of dietary EPA/DHA on triacylglycerol relative to phospholipid synthesis from intermediary 1,2-diacylglycerol in rat liver in vivo. This metabolic alteration was accompanied by a substantially lower amount (in mumol/g liver) of arachidonic acid and higher levels of EPA plus DHA in the triacylglycerol, choline glycerophospholipid (CGP), and ethanolamine glycerophospholipid (EGP) of the FO group. A moderately higher labelling of the EGP from [3H]glycerol was observed in the FO as compared to the SO group (as evidenced by CGP/EGP radioactivity ratios of 1.3:1 and 1.8:1, respectively). The present study provides in vivo evidence for a dampening effect of dietary fish oil on the synthesis of liver triacylglycerol relative to phospholipid and a moderate alteration of de novo synthesis of individual phospholipids.
Yeo
Y K
YK
Department of Dairy Sciences, Kyungpook National University, Taegu, Korea.
Holub
B J
BJ
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004041:Dietary Fats / Q000494:pharmacology*; D005227:Fatty Acids / Q000032:analysis; D005395:Fish Oils / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism*; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010743:Phospholipids / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000096:biosynthesis*
D004041:Dietary Fats; D005227:Fatty Acids; D005395:Fish Oils; D010743:Phospholipids; D014280:Triglycerides