Showing papers on "Docosahexaenoic acid published in 1988"

Adverse Metabolic Effect of Omega-3 Fatty Acids in Non-Insulin-Dependent Diabetes Mellitus

Abstract: Increased interest in using omega-3 fatty acids led us to examine their metabolic effects in six men with type II (non-insulin-dependent) diabetes mellitus After 1 month of a diet supplemented with these fatty acids, the patients' fasting glucose rose from 131 +/- 13 to 153 +/- 13 mmol/L (P = 003) and glucose area during a mixed meal profile rose by 22% (P = 004) Basal hepatic glucose output rose from 97 +/- 9 to 122 +/- 8 mg/m2 min (P = 0004) but glucose disposal rates measured by euglycemic glucose clamp were unchanged Fasting insulin levels were similar; peak insulin levels stimulated by meals or intravenous glucagon fell by 30% and 39%, respectively Plasma and erythrocyte content of omega-3 fatty acid rose significantly After omega-3 fatty acid withdrawal, fasting glucose returned to baseline Omega-3 fatty acid treatment in type II diabetes leads to rapid but reversible metabolic deterioration, with elevated basal hepatic glucose output and impaired insulin secretion but unchanged glucose disposal rates Caution should be used when recommending omega-3 fatty acids in type II diabetic persons

Effect of Different Levels of Omega-3 and Omega-6 Fatty Acids on Azoxymethane-induced Colon Carcinogenesis in F344 Rats

Abstract: The effect of various levels of dietary Menhaden fish oil containing omega-3 fatty acids plus corn oil containing omega-6 fatty acids fed during the postinitiation phase of colon carcinogenesis was studied in male F344 rats. Starting at 5 weeks of age, groups of animals were fed the 5% corn oil (5% CO) diet. At 7 weeks of age, all animals except the vehicle-treated controls were administered s.c. injections of azoxymethane (15 mg/kg body wt/week for 2 weeks). 4 days after carcinogen or vehicle treatment, groups of animals were transferred to experimental diets containing 4% Menhaden oil + 1% corn oil (4% MO + 1% CO), 23.5% corn oil (23.5% CO), 17.6% corn oil + 5.9% Menhaden oil (17.6% CO + 5.9% MO), 11.8% corn oil + 11.8% Menhaden oil (11.8% CO + 11.8% MO), or 5.9% corn oil + 17.6% Menhaden oil (5.9% CO + 17.6% MO) and fed these diets until termination of the experiment at Week 38 after carcinogen treatment. An additional group consuming a 5% CO diet was continued on these diets. Colon mucosal ornithine decarboxylase activity and microsomal fatty acid composition of colon mucosa were measured in vehicle-treated animals fed experimental diets for 14 weeks. Fatty acids were also analyzed in the microsomal fraction of colon tumors at termination of the experiment. The body weights of animals fed various experimental diets were comparable. Feeding of high fat diets containing 17.6% CO + 5.9% MO, 11.8% CO + 11.8% MO, or 5.9% CO + 17.6% MO significantly inhibited the incidence (percentage of animals with tumors) of colon adenocarcinomas compared to that of 23.5% CO diet. However, the multiplicity (number of tumors/rat) of colon adenocarcinomas was significantly inhibited only in groups fed the 5.9% CO + 17.6% MO compared to those fed the 23.5% CO diet. The incidence and multiplicity of adenocarcinomas were greater in animals fed the 23.5% CO diet compared to those fed the 5% CO diet. Colonic mucosal ornithine decarboxylase activity was lower in animals fed the 11.8% CO + 11.8% MO, 5.9% CO + 17.6% MO, 5% CO, and 4% MO + 1% CO diets compared to the levels in animals fed the 23.5% CO diet. The increasing levels of Menhaden oil in the diet significantly increased the omega-3 fatty acids such as eicosapentaenoic acid and docosahexaenoic acid and decreased the omega-6 fatty acids such as linoleic acid, linolenic acid, and arachidonic acid in microsomal fractions from colonic mucosa and tumors.

Effect of dietary supplementation with fish oil lipids on mild asthma.

Abstract: Recruitment of inflammatory leucocytes to the airways may play a part in the pathogenesis of asthma. As dietary enrichment with fish oil lipids can suppress leucocyte function, the effect of these lipids on asthma control and neutrophil function was studied in 20 subjects with mild asthma. Twelve subjects received capsules containing 3.2 g of eicosapentaenoic acid and 2.2 g of docosahexaenoic acid daily and eight subjects received placebo capsules containing olive oil for 10 weeks in a double blind fashion. Baseline specific airways conductance, airways responsiveness to histamine and exercise, diurnal peak expiratory flow, symptom scores, and bronchodilator use were measured. Neutrophil fatty acid composition was evaluated by gas chromatography, calcium ionophore induced neutrophil leukotriene (LT)B4 and LTB5 generation were measured by reverse phase high performance liquid chromatography and radioimmunoassay, and neutrophil chemotactic responses to formyl-methionyl-leucyl-phenylalanine (FMLP) and LTB4 were assessed by a microchemotaxis technique. Although the fish oil supplemented diet produced a greater than 10 fold increase in the eicosapentaenoic acid content of neutrophil phospholipids, there was no significant change in airways responsiveness to histamine or any change in any of the clinical measurements. After dietary supplementation with fish oil there was a 50% inhibition of total LTB (LTB4 + LTB5) generation by ionophore stimulated neutrophils and neutrophil chemotaxis was substantially suppressed. Neutrophil function remained unchanged in the placebo group. It is concluded that in subjects with mild asthma a fish oil enriched diet attenuates neutrophil function without changing the severity of asthma.

Effect of dietary cholesterol and/or omega 3 fatty acids on lipid composition and delta 5-desaturase activity of rat liver microsomes.

Abstract: Male weanling rats were fed for 28 d a purified diet containing 20% (wt/wt) fat providing high levels of either saturated fat or alpha-linolenic acid or eicosapentaenoic and docosahexaenoic acids with or without 2% (wt/wt) cholesterol supplementation. Effect of diet on rate of desaturation of eicosatrienoic acid (20:3 omega 6) and lipid composition of liver microsomal membranes was examined. The desaturation of 20:3 omega 6 to arachidonic acid (20:4 omega 6) was higher in rats fed linseed oil and lower in rats fed fish oil than in control animals fed the beef tallow diet. The desaturation of 20:3 omega 6 was lower in rats fed beef tallow or linseed oil diets supplemented with cholesterol than in the respective unsupplemented diet. Inclusion of 2% (wt/wt) cholesterol in the fish oil diet failed to affect synthesis of 20:4 omega 6 from 20:3 omega 6. These in vitro changes in delta 5-desaturase activity are consistent with the diet-induced alterations observed in the fatty acid composition of microsomal membranes. Both free cholesterol and cholesterol ester in the microsomal membrane were higher in rats fed beef tallow or linseed oil diets supplemented with exogenous cholesterol than in the respective unsupplemented diet, and only free cholesterol was higher in rats fed the fish oil diet supplemented with cholesterol. Feeding fish oil appears to prevent both the inhibition of 20:4 omega 6 biosynthesis and the accumulation of cholesterol ester that were apparent when 2% cholesterol was added to either beef tallow or linseed oil diets.

Induction of intracellular superoxide radical formation by arachidonic acid and by polyunsaturated fatty acids in primary astrocytic cultures.

Abstract: The effects of arachidonic acid and other polyunsaturated fatty acids (PUFAs) on both oxidative and metabolic perturbation were studied in primary cultures of rat cerebral cortical astrocytes. In the presence of 0.1 mM arachidonic acid, the rate of the reduction of nitroblue tetrazolium (NBT) to nitroblue formazan (NBF) was stimulated from 0.65 +/- 0.10 to 1.43 +/- 0.15 and from 0.092 +/- 0.006 to 0.162 +/- 0.009 nmol/min/mg protein in intact and broken cell preparations, respectively. The rate of superoxide radical formation, as measured by the superoxide dismutase (SOD)-inhibitable NBT reduction was 0.042 nmol/mg protein in broken cells and was negligible in intact cells. The latter is due to the impermeability of SOD into the intact cell preparation. NBF formation in intact astrocytes stimulated by arachidonic acid was both time- and dose-dependent. Other PUFAs, including linoleic acid, linolenic acid, and docosahexaenoic acid, were also effective in stimulating NBF formation in astrocytes, whereas saturated palmitic acid and monounsaturated oleic acid were ineffective. Similar effects of these PUFAs were observed in malondialdehyde formation in cells and lactic acid accumulation in incubation medium. These data indicate that both membrane integrity and cellular metabolism were perturbed by arachidonic acid and by other PUFAs. The sites of superoxide radical formation appeared to be intracellular and may be associated with membrane phospholipid domains, because liposome-entrapped SOD, which was taken up by intact astrocytes, reduced the level of superoxide radicals and lactic acid content, whereas free SOD was not effective.

Differential effects of dietary linoleic and α-linolenic acid on lipid metabolism in rat tissues

Abstract: Comparative effects of feeding dietary linoleic (safflower oil) and α-linolenic (linseed oil) acids on the cholesterol content and fatty acid composition of plasma, liver, heart and epididymal fat pads of rats were examined. Animals fed hydrogenated beef tallow were used as isocaloric controls. Plasma cholesterol concentration was lower and the cholesterol level in liver increased in animals fed the safflower oil diet. Feeding the linseed oil diet was more effective in lowering plasma cholesterol content and did not result in cholesterol accumulation in the liver. The cholesterol concentration in heart and the epididymal fat pad was not affected by the type of dietary fatty acid fed. Arachidonic acid content of plasma lipids was significantly elevated in animals fed the safflower oil diet and remained unchanged by feeding the linseed oil diet, when compared with the isocaloric control animals fed hydrogenated beef tallow. Arachidonic acid content of liver and heart lipids was lower in animals fed diets containing safflower oil or linseed oil. Replacement of 50% of the safflower oil in the diet with linseed oil increased α-linolenic, docosapentaenoic and docosahexaenoic acids in plasma, liver, heart and epididymal fat pad lipids. These results suggest that dietary 18∶2ω6 shifts cholesterol from plasma to liver pools followed by redistribution of 20∶4ω6 from tissue to plasma pools. This redistribution pattern was not apparent when 18∶3ω3 was included in the diet.

Exogenous Arachidonic Acid Promotes Insulin Release From Intact or Permeabilized Rat Islets by Dual Mechanisms: Putative Activation of Ca2+ Mobilization and Protein Kinase C

Abstract: A number of indirect studies suggest a role for endogenous arachidonic acid (AA) in pancreatic islet function. To probe the effects of this fatty acid, AA and other polyunsaturated fatty acids were exogenously provided in Ca2+-free medium to avoid the formation of insoluble or impermeant Ca2+-arachidonate complexes. Concentrations of AA of greater than or equal to 3 microM induced potent and sustained but reversible 45Ca efflux from prelabeled intact (or digitonin-permeabilized) islets; AA also induced insulin release at somewhat higher concentrations. Other unsaturated fatty acids (erucic, oleic, linoleic, linolenic, dihomo-gamma-linolenic, eicosapentaenoic, docosahexaenoic acids) were generally less active than AA itself, indicating a structure-function relationship. The effects of AA were saturable, were inhibitable by cooling, and were not accompanied in parallel by 51Cr release or trypan blue retention, suggesting a nontoxic mechanism. At low concentrations (3.3-16 microM), at which AA does not stimulate insulin release, AA-induced 45Ca efflux was not reduced by pretreatment with ionomycin (to deplete membrane-bound Ca2+ stores), suggesting stimulation of Ca2+ extrusion through the plasma membrane. At higher concentrations (greater than or equal to 25 microM), at which AA promotes insulin release, further Ca2+ efflux was stimulated, which was blunted by pretreatment with ionomycin (as well as by trifluoperazine). Conversely, pretreatment with AA obliterated the effects of ionomycin (3 microM) on cellular Ca2+ mobilization. Thus, AA also mobilizes Ca2+ from intracellular organelles, leading to a rise in free cytosolic Ca2+ (as previously reported). AA-induced 45Ca efflux and insulin release were independent of the presence of extracellular Na+ and did not require the oxygenation of AA. Dose-response curves comparing 45Ca efflux and insulin secretion suggested that AA also stimulates hormone release by at least one other mechanism in addition to Ca2+ mobilization. This second stimulatory effect of AA could be seen in digitonin-permeabilized islets, where changes in cytosolic free Ca2+ concentration were vitiated by EGTA-containing buffers. Such secretion was also saturable and was inhibited by cooling or by spermine (which inhibits protein kinase C in the islet). Furthermore, AA-induced secretion from either intact or permeabilized islets was blunted by prolonged pretreatment of islets with a phorbol ester to deplete them of protein kinase C. Thus, exogenous arachidonic acid seems to be a complete secretagogue, having stimulatory effects both on Ca2+ mobilization and Ca2+-related secretory processes, putatively the activation of protein kinase C.

Alteration in fatty acid composition of adult rat brain capillaries and choroid plexus induced by a diet deficient in n-3 fatty acids: slow recovery after substitution with a nondeficient diet.

Abstract: Wistar rats were fed for three generations with a semisynthetic diet containing either 1.5% sunflower oil (940 mg% of C18:2n-6, 6 mg% of C18:3n-3) or 1.9% soya oil (940 mg% of C18:2n-6, 130 mg% of C18:3n-3). At 60 days of age, the male offspring of the third generation were killed. The fatty acyl composition of isolated capillaries and choroid plexus was determined. The major changes noted in the fatty acid profile of isolated capillaries were a reduction (threefold) in the level of docosahexaenoic acid and, consequently, a fourfold increase in docosapentaenoic acid in sunflower oil-fed animals. The total percentage of poly-unsaturated fatty acids was close to that in the soya oil-fed rats, but the ratio of n-3/n-6 fatty acids was reduced by threefold. In the choroid plexus, the C22:6n-3 content was also reduced, but by 2.6-fold, whereas the C22:5n-6 content was increased by 2.3-fold and the ratio of n-3/n-6 fatty acids was reduced by 2.4-fold. When the diet of sunflower oil-fed rats was replaced with a diet containing soya oil at 60 days of age, the recovery in content of n-6 and n-3 fatty acids started immediately after diet substitution; it progressed slowly to reach normal values after 2 months for C22:6n-5 and 2.5 months for C22:6n-3. The recovery in altered fatty acids of choroid plexus was also immediate and very fast. Recovery in content of C22:5n-6 and C22:6n-3 was complete by 46 days after diet substitution.

Inhibition of apolipoprotein secretion and phosphatidate phosphohydrolase activity by eicosapentaenoic and docosahexaenoic acids in the perfused rat liver

Abstract: Infusion of albumin-bound eicosapentaenoic acid (EPA) docosahexaenoic acid (DHA), or oleic acid (OA) in perfused rat livers was carried out for two hours at a rate that maintained the perfusate concentration at 1 mmol/L. When compared with fatty acid-poor albumin alone, triacylglycerol (TAG) output was not significantly increased with DHA or EPA, whereas OA infusion resulted in a twofold increase. Incorporation of labeled leucine into VLDL apo B-100, apo B-48, apo E, and apo Cs was decreased by 50% by DHA or EPA compared with OA. The total phosphatidate phosphohydrolase activity was decreased by 35% with DHA or EPA compared to oleic acid or albumin alone. In no case was there a significant change in the distribution of activity between the microsomal and cytosolic factions. Fatty acid infusion did not significantly change the liver TAG content. Total liver lipids, microsomal lipids, and lipids of secreted VLDL were enriched with the infused fatty acids. The degree of enrichment for secreted TAG averaged 24% for OA and 36% for DHA or EPA. The effects of DHA and EPA on PPH activity and on apo B secretion in feeding experiments with marine oils rich in these acids may relate to changes in the fatty acid composition of liver membranes.

The lipid content and fatty acid composition of various marine species from southern Australian coastal waters

Abstract: 1. 1. The total lipids were extracted from the flesh of 25 species of temperate Australian fish and cephalopods and the fatty acid composition was determined by capillary gas chromatography. 2. 2. All species were rich in palmitic acid (range 16–25% of total fatty acids) and docosahexaenoic acid (range 15–53%). There were variable amounts of arachidonic acid (range 1–15%) and eicosapentaenoic acid (range 3–23%). 3. 3. The omnivorous species of bony fish contained more arachidonic acid (mean 10%) than the carnivorous bony fish (mean 5%). The cartilaginous species were relatively low in eicosapentaenoic acid (mean 5%) whereas the cephalopods contained high levels of this fatty acid (mean 18%).

Docosahexaenoic acid and other dietary polyunsaturated fatty acids suppress leukotriene synthesis by mouse peritoneal macrophages.

Abstract: The efficacy of individual ω-t-3 polyunsaturated fatty acids (PUFA) in altering eicosanoid synthesis in peritoneal macrophages was studied by feeding mice for 10 days a diet containing 2 wt% fat, which included 0.5 wt% ethyl esters of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or linolenic acid (LNA). Upon stimulation with calcium ionophore A23187, macrophages from these animals produced significantly lower amounts of leukotriene C4, leukotriene B4 and 12-hydroxyeicosatetraenoic acid, prostaglandin E2 and 6-keto prostaglandin F1α compared with those obtained from animals on the diets containing olive oil or safflower oil. The decrease in leukotriene synthesis was similar in the animals fed DHA, EPA or LNA diets. This depression of eicosanoids by DHA and EPA was associated with decreased levels of arachidonic acid (AA); however, LA that altered eicosanoids did not have the same effect on AA levels.

Effects of chronic diabetes mellitus on the electrical and contractile activities, 45Ca2+ transport, fatty acid profiles and ultrastructure of isolated rat ventricular myocytes.

Abstract: The effects of chronic experimental diabetes on electrophysiological properties, contractile behavior,45Ca2+ transport, fatty acid profiles and ultrastructural characteristics were studied in enzymatically dissociated ventricular myocytes. Diabetes was induced in rats by streptozotocin administration and animals were killed 8–10 weeks later. Myocytes from diabetic rats exhibited electrical behavior similar to that of myocytes from control rats, but their contractile properties were altered. Their sensitivity of the twitch contractions to various positive and negative inotropic agents (isoproterenol, norepinephrine, phenylephrine, acetylcholine, ouabain and veratridine) was greatly diminished. However, a part of the contractile response (the tonic, sustained contractions) were increased in the diabetic myocytes, indicating that the changes are not caused by a decreased sensitivity of myofilaments. Furthermore, the diabetic myocytes exhibited also significant decrease in total Ca2+ content. The fatty acid profile in the diabetic group was changed mainly in that there were slightly elevated levels of docosahexaenoic acid and diminished levels of palmitic acid. The ultrastructure of the diabetic myocytes was affected only slightly. These investigations offer for the first time a comprehensive picture of changes related to diabetic cardiomyopathy as they occur at the level of cardiomyocytes.

Changes in the fatty acids pattern of red blood cell phospholipids induced by type of milk, dietary nucleotide supplementation, and postnatal age in preterm infants.

Abstract: The fatty acid profile of red blood cell phospholipids and the total phospholipid and cholesterol contents of erythrocyte membrane in preterm infants in the first month of life were studied. Influences of human milk and adapted formula and dietary nucleotides supplementation at a level similar to that found in human milk were evaluated. Nineteen preterm newborn infants with adequate weight for gestational age were fed their own mother's preterm human milk, 18 with a standard milk formula and 18 with the same formula supplemented with nucleotides. Blood samples were obtained at birth from cord blood, and at 30 days of age. At 1 month of life, linoleic acid rose in formula fed infants compared to those fed human milk (p less than 0.05) and relative amounts of 20:3w6, 20:4w6, 22:4w6, 22:5w6, and total polyunsaturates of the w6 series greater than 18 carbon atoms were significantly decreased in standard milk formula fed infants (p less than 0.05-0.01). No significant differences for these fatty acids were found between human milk and nucleotide milk formula infants. Docosahexaenoic acid (22:6w3) decreased from birth to 1 month of age in formula fed infants (p less than 0.01) but not in human milk fed infants. Infants fed nucleotide milk formula showed intermediate values for 20:3w6 and 20:4w6 (p less than 0.1) between infants fed human milk and those fed standard milk formula.(ABSTRACT TRUNCATED AT 250 WORDS)

Membrane lipid alteration: Effect on cellular uptake of mitoxantrone

Abstract: We have studied the effect of membrane structural alteration on the cellular association of the anticancer drug mitoxantrone whose uptake is not carrier-mediated. Membrane fatty acids of L1210 cells were modified by incubating the cells with the highly unsaturated docosahexaenoic acid (22:6), which results in isolated plasma membranes with 37% of the fatty acids as 22:6, or with the monounsaturated oleic acid (18:1), which results in 58% of the fatty acids as 18:1. The rate of uptake by 22:6-enriched cells during the first min was 62% greater than by those enriched with 18:1. The higher rate was recorded at 0.5-16 microM, pH 6.6-7.6 and temperatures 10-40 C. The difference in cell-associated drug apparently was not due simply to a change in mitoxantrone solubility as measured by partitioning of the drug in lipophilic-hydrophilic systems containing lipids from the fatty-acid altered cells. We conclude that the type of fatty acids contained in L1210 cell membranes can affect the cell association of mitoxantrone. This effect could be on transmembrane flux or be due to differences in binding of the drug to intracellular structures.

Degradation of phospholipid molecular species during experimental cerebral ischemia in rats.

Abstract: Previous investigators have shown that free fatty acids that accumulate during ischemia are an indicator of evolution in ischemic brain damage. Our study describes the temporal relations between free fatty acid accumulation and degradation of phospholipid molecular species after cerebral ischemia. Using the four-vessel occlusion model of adult Wistar rats, we analyzed quantitatively the cerebral phospholipid molecular species of diacyl phosphatidylcholine and diacyl phosphatidylethanolamine and released free fatty acids during ischemia. Total diacyl phosphatidylcholine molecular species decreased gradually but did not show any significant difference even at 60 minutes. By contrast, total diacyl phosphatidylethanolamine abruptly decreased after 5 minutes and continued to decrease significantly thereafter. Polyunsaturated molecular species showed a higher ratio of degradation than saturated and monounsaturated molecular species of either phosphatidylcholine or phosphatidylethanolamine. Total free fatty acid accumulated according to the time elapsed, and statistical significance was obtained after 10 minutes. Free arachidonic and docosahexaenoic acids were attributed to these significant accumulations at 10, 15, and 30 minutes. At 60 minutes, individual free fatty acids increased nonspecifically. Free fatty acids, which are hydrolyzed from phospholipid classes, are known to be further metabolized to bioactive substances such as prostaglandins and leukotrienes. Rapid degradation of phospholipid molecular species, especially of diacyl polyunsaturated molecular species, could be an important finding to membrane perturbation. Effective prevention of these changes might enhance tolerance to ischemic brain damage.

Influence of diet with different lipid composition on neutrophil chemiluminescence and disease activity in patients with rheumatoid arthritis.

Abstract: Neutrophil chemiluminescence was determined in patients with active rheumatoid arthritis. Twelve patients were randomly assigned either to a diet high in polyunsaturated fatty acids supplemented with eicosapentaenoic and docosahexaenoic acids or to a diet high in saturated fatty acids. A correlation with clinical and laboratory parameters is also reported. No statistical difference was observed in neutrophil chemiluminescence and in clinical parameters in the group of patients treated with a diet high in saturated fatty acids. Fish oil ingestion resulted in subjective alleviation of active rheumatoid arthritis and reduction of neutrophil chemiluminescence. This study corroborates the hypothesis of an anti-inflammatory role for polyunsaturated fatty acids in patients with chronic inflammatory diseases.

Comparison of Pond‐Raised and Wild Red Drum (Sciaenopsocellatus) with Respect to Proximate Composition, Fatty Acid Profiles, and Sensory Evaluations

Abstract: The proximate composition, fatty acid profiles, and the sensory characteristics of pond-raised red drum were compared to wild red drum. The proximate compositions and sensory characteristics were similar for pond-raised and wild red drum. The major difference between samples was in the fatty acid profiles. The pond-raised red drum had higher linoleic acid and lower docosahexaenoic acid concentrations than the wild fish samples. The eicosapentaenoic acid concentrations were similar in both pond-raised and wild red drum.

Free fatty acids for treatment or prophylaxis of rheumatoid arthritis

Abstract: Eicosapentaenoic acid and docosahexaenoic acid, in free acid form or in the form of a pharmaceutically acceptable salt thereof, are useful in treating rheumatoid arthritis. The free fatty acids (or salts) were an order of magnitude more effective in treating arthritis than the same amount of EPA and DHA in their triglyceride form.

Dietary ω3 polyunsaturated fatty acids augment endothelium-dependent relaxation to bradykinin in coronary micro vessels of the pig

Abstract: 1. The effects of chronic dietary supplementation with omega 3 polyunsaturated fatty acids on endothelium-dependent relaxations were examined in isolated coronary microvessels of the pig. 2. Animals were maintained for four weeks with or without dietary supplementation of purified eicosapentaenoic acid (3.5 g daily) and docosahexaenoic acid (1.5 g daily). Fatty acid profiles of plasma lipids showed that only the fraction of eicosapentaenoic acid increased by the treatment, together with a decrease of that of arachidonic acid. 3. In the treated group, endothelium-dependent relaxations to bradykinin were significantly augmented, while contractions to acetylcholine or relaxations to nitroprusside were unaltered. 4. These results indicate that dietary omega 3 polyunsaturated fatty acids (mainly eicosapentaenoic acid) augment endothelium-dependent relaxations in coronary microvessels of the pig, without changing the ability of vascular smooth muscle to contract or relax.

Changes in the fatty acid profiles of plasma lipid fractions induced by dietary nucleotides in infants born at term.

Abstract: This study was designed to determine the polyunsaturated fatty acid (PUFA) composition of plasma lipid fractions in newborn infants fed human milk (HM), milk formula (MF) or nucleotide-supplemented milk formula (NMF) during the first month of life. Linoleic acid was increased in infants fed formulas in all plasma lipid fractions with respect to those fed HM. Plasma phospholipids in MF-fed infants had lower percentages of PUFA of both omega 6 and omega 3 series, namely arachidonic and docosahexaenoic acids, than those fed HM or NMF; the unsaturation index was decreased in infants fed MF as compared to those fed HM or NMF. Arachidonic acid showed a similar behaviour in plasma cholesteryl esters as in phospholipids. No changes for long chain PUFA among the groups studied were observed for plasma triglycerides and free fatty acids. These results support previous findings that dietary nucleotides are involved in the regulation of desaturation and elongation of linoleic and linolenic acid to their longer superior homologous fatty acids. We suggest that dietary nucleotides may reverse the partial inhibition of delta 5-desaturase caused by an excess of linoleic acid in the diet during early postnatal life.