The influence of dietary marine oil (Polepa) and evening primrose oil (Efamol) on prostaglandin production by the rat mesenteric vasculature.
The interactions of n-6 and n-3 fatty acids on prostaglandin metabolism in the isolated rat mesenteric vessels were studied. Sprague-Dawley rats (200-220 g) were fed for two weeks a fat-free semi-synthetic diet supplemented with 10% by weight of different combinations of Evening Primrose Oil (Efamol), a rich source of linoleic acid (LA) and gamma-linolenic acid (GLA), the immediate precursor of dihomo-gamma-linolenic acid (DGLA), and Polepa (POL), a marine oil rich in eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. The combinations of supplement were as follows: 9% Efamol - 1% POL, 8% Efamol - 2% POL, 7% Efamol - 3% POL, 6% Efamol - 4% POL, 5% Efamol - 5% POL. The outflow of thromboxane (TxB2), prostacyclin (6-keto-PGF1 alpha), PGE2, and PGE1 was decreased in relation to the proportion of marine oil in the diet, except for the group which received 8% Efamol - 2% POL, and which showed an increase in 6-keto-PGF1 alpha, PGE2, and PGE1. The decrease in TxB2 was much greater than those of 6-keto-PGF1 alpha or PGE2, while PGE1 followed the same pattern as prostacyclin and PGE2. These results suggest that n-3 fatty acids, at high concentrations, inhibits conversion of both DGLA and AA to eicosanoids. Low concentrations of fish oil may, in contrast, increase formation of desirable 1 and 2 series eicosanoids.
D000284:Administration, Oral; D000818:Animals; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage / Q000494:pharmacology; D005228:Fatty Acids, Essential; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology*; D005395:Fish Oils / Q000008:administration & dosage / Q000494:pharmacology*; D008041:Linoleic Acids / Q000378:metabolism; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000378:metabolism; D031665:Oenothera biennis; D010938:Plant Oils; D011453:Prostaglandins / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D017965:gamma-Linolenic Acid
D004041:Dietary Fats; D005228:Fatty Acids, Essential; D005231:Fatty Acids, Unsaturated; D005395:Fish Oils; D008041:Linoleic Acids; D010938:Plant Oils; D011453:Prostaglandins; C028498:evening primrose oil; D017965:gamma-Linolenic Acid; D015118:Eicosapentaenoic Acid