Effects of dietary n-6/n-3 ratios on lipid and prostaglandin E2 metabolism in rat gastric mucosa.
The effects of increased dietary n-3 polyunsaturated fatty acids on gastric mucosal lipid metabolism were studied in rats fed for 8 weeks with different combinations of fish and corn oils. Lipid composition, ex vivo prostaglandin E2 (PGE2) production and enzymatic activities involved in phospholipid metabolism and peroxisomal oxidative catabolism of fatty acids and PGE2 were examined. With dietary n-6/n-3 compositional ratios ranging between 75 and 3.3 it was observed that: (i) the arachidonic acid-to-eicosapentaenoic acid ratio (AA/EPA) fell from infinity to 3.1 and 5.1 in phosphatidylcholines (PC) and phosphatidylethanolamines (PE), respectively; (ii) ex vivo production of PGE2 was lowered by a factor of about 2; and (iii) gastric phospholipase A2 activity was enhanced by 32%. With dietary n-6/n-3 ratio lower than 3.3, stimulation of PGE2-CoA oxidase activity was observed whilst the PGE2 level remained constant. These data suggest that the fish oil-induced decrease in ex vivo PGE2 production is more closely related to a decrease in the membrane AA level than to an enhanced oxidative catabolism of PGE2.
Grataroli
R
R
Institut National de la Santé et de la Recherche Médicale, Unité 130, Marseille, France.
Vamecq
J
J
Poupaert
J H
JH
Léonardi
J
J
Termine
E
E
Lafont
H
H
Nalbone
G
G
D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000378:metabolism; D000818:Animals; D003314:Corn Oil / Q000008:administration & dosage*; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D015232:Dinoprostone / Q000096:biosynthesis / Q000378:metabolism*; D005395:Fish Oils / Q000008:administration & dosage*; D005753:Gastric Mucosa / Q000378:metabolism*; D050356:Lipid Metabolism; D008245:Lysophospholipase / Q000378:metabolism; D008297:Male; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D051381:Rats; D017208:Rats, Wistar
D004042:Dietary Fats, Unsaturated; D005395:Fish Oils; D003314:Corn Oil; D008243:1-Acylglycerophosphocholine O-Acyltransferase; D010741:Phospholipases A; D054467:Phospholipases A2; D008245:Lysophospholipase; D015232:Dinoprostone