Changes In Fatty Acid Pattern Research Articles

Influence of blue mussel (Mytilus edulis) intake on fatty acid composition in erythrocytes and plasma phospholipids and serum metabolites in women with rheumatoid arthritis

Intake of blue mussels decreased disease activity in women with rheumatoid arthritis (RA) in the randomized cross-over MIRA (Mussels, inflammation and RA) trial. This study investigates potential causes of the decreased disease activity by analysing fatty acid composition in erythrocytes and plasma phospholipids and serum metabolites in samples from the participants of the MIRA trial. Twenty-three women completed the randomized 2 × 11-week cross-over dietary intervention, exchanging one cooked meal per day, 5 days a week, with a meal including 75 g blue mussels or 75 g meat. Fatty acid composition in erythrocytes and plasma and 1H Nuclear Magnetic Resonance (1H NMR) metabolomics data were analysed with multivariate data analysis. Orthogonal Projections to Latent Structures with Discriminant Analysis (OPLS-DA) and OPLS with effect projections (OPLS-EP) were performed to compare the two diets. The fatty acid profile in erythrocytes was different after intake of blue mussels compared to the control diet, and all samples were correctly classified to either the blue mussel diet or control diet. Changes following blue mussel intake included significant increases in omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) at the group level but not for all individuals. The fatty acid profile in plasma phospholipids and 1H NMR serum metabolites did not differ significantly between the diets. To conclude, modelling fatty acids in erythrocytes may be a better biomarker for seafood intake than only EPA and DHA content. The change in fatty acid pattern in erythrocytes could be related to reduction in disease activity, although it cannot be excluded that other factors than omega-3 fatty acids potentiate the effect.

241 Changes in fatty acid pattern of depot fat tissue in young pancreatic duct ligated pigs – used as a model for humans with pancreatic exocrine insufficiency

Objectives Most CF patients suffer from pancreatic exocrine insufficiency (PEI) causing maldigestion and malabsorption of fat. PEI patients are prone to deficiency in essential fatty acids. This study aimed to test whether fatty acid (FA) pattern of fat tissue is affected in pigs with PEI induced by pancreatic duct ligation (PL). Methods 9 piglets underwent surgery at the age of 7 weeks [n = 5 sham OP = controls; n = 4 PL (PL7)], 3 pigs underwent PL when aged 16 weeks (PL16). No pancreatic enzyme therapy was given to PL-pigs. A complete diet was fed containing soy oil and linseed oil (total 115 g crude fat/kg diet dm). All pigs were euthanized at the age of 26 weeks and neck fat tissue was sampled. FA were analysed by GC (ATI Unicam 610, SP-2560 column, Supelco; carrier gas: N). Results Total tract crude fat digestibility (%) was reduced in PL7 (33.4) and PL16 (38.4) compared to controls (80.1). Although diet fed and age at euthanasia were identical, FA pattern of fat tissue showed significantly changes in PL7. Saturated FA (C16:0 and C18:0) increased, while C18:3n3 decreased. Conclusion The increased C16:0 and C18:0 content of fat tissue in PL7 is supposed to be an effect of the relatively higher rate of de novo fat synthesis (Wood et al. 2008) in PL pigs. The fact that in PL16 pigs FA pattern did not differ from controls (except for an increase of C18:0) indicates that these changes need some time or are related to the age when PEI is induced. Whether the finding of the changes in FA pattern of the neck fat tissue in PL7 is a result of affected digestion of different FA or impaired metabolism after absorption is yet unclear.

Change in the fatty acid pattern of erythrocyte membrane phospholipids after oral supplementation of specific fatty acids in patients with gastrointestinal diseases

The fatty acid pattern of membrane phospholipids is suggested to affect membrane fluidity and epithelial barrier function as a result of membrane fatty acid unsaturation. The incorporation of n-3 polyunsaturated fatty acids (PUFAs) into membrane phospholipids may diminish inflammatory potential in patients with gastrointestinal diseases. The aim of this study was to improve the fatty acid profile of erythrocyte membrane phospholipids after oral supplementation of specific fatty acids in patients with maldigestion and/or malabsorption. We conducted a randomized, double-blind, controlled trial. A total of 48 patients with gastrointestinal diseases received either fat-soluble vitamins A,D,E,K (ADEK) or ADEK plus fatty acids alpha-linolenic acid (ALA), docosahexaenoic acid (DHA) and medium-chain triglycerides (FA-ADEK) for 12 weeks. The fatty acid profile of erythrocyte membrane phospholipids, dietary intake, plasma antioxidant vitamins and serum gamma-glutamyl transferase (GGT) were evaluated at baseline, 8 and 12 weeks after supplementation. Supplementation with FA-ADEK increased ALA, DHA and eicosapentaenoic acid (EPA) concentrations of erythrocyte membrane phospholipids by 0.040, 1.419 and 0.159%, respectively, compared with ADEK supplementation (-0.007, 0.151 and 0.002%, respectively) after 12 weeks (all P<or=0.001). Serum GGT activity decreased in patients receiving FA-ADEK compared with those receiving ADEK with a significant difference after 8 weeks. The significant change in erythrocyte membrane fatty acid pattern demonstrates the incorporation of orally administered n-3 PUFA in patients with maldigestion and malabsorption. The increase in ALA and DHA, as well as the conversion of ALA to EPA is attributed to the supplementation of sufficient amounts of ALA and DHA, respectively. Serum GGT activity decreased in response to decreased oxidative stress.

Short-term variation of nutritive and metabolic parameters in Temora longicornis females (Crustacea, Copepoda) as a response to diet shift and starvation

Changes in fatty acid patterns, digestive and metabolic enzyme activities and egg production rates (EPR) were studied in the small calanoid copepod Temora longicornis. Female copepods were collected in spring 2005 off Helgoland (North Sea). In the laboratory one group of copepods was fed with the cryptophycean Rhodomonas baltica for a period of 3 days. Another group of copepods was maintained without food. According to the fatty acid patterns, animals from the field were feeding on a more detrital, animal-based and to a minor extent to a diatom-based diet. Under laboratory conditions, females rapidly accumulated fatty acids such as 18:4 (n-3), 18:3 (n-3) and 18:2 (n-6) which are specific of R. baltica. Diatom-specific fatty acids such as 16:1 (n-7) were strongly reduced. In fed animals the activities of digestive and metabolic enzymes remained constant and egg production rates were highest on day 2. Starving animals, in contrast, showed significantly reduced faecal pellet production and EPR. Proteolytic enzyme activity decreased rapidly within 24 h and remained at a low level until the end of the experiment. Citrate synthase decreased continuously as well. T. longicornis rapidly reacts to dietary changes and food depletion. It has limited energy stores and, thus, strongly depends on continuous food supply.

Artificial rearing with docosahexaenoic acid and n-6 docosapentaenoic acid alters rat tissue fatty acid composition

Docosahexaenoic acid (DHA; 22:6n-3) and n-6 docosapentaenoic acid (DPAn-6; 22:5n-6) are components of enriched animal feed and oil derived from Schizochytrium species microalgae. A one generation, artificial rearing model from day 2 after birth onward (AR) and a dam-reared control group (DAM) were used to examine DPAn-6 feeding on the fatty acid composition of various rat tissues at 15 weeks of age. Four AR diets were based on an n-3 fatty acid-deficient, 18:2n-6-based artificial milk with 22:6n-3 and/or 22:5n-6 added: AR-LA, AR-DHA, AR-DPAn-6, and AR-DHA+DPAn-6. The 22:6n-3 levels for the DAM, AR-DHA, and AR-DHA+DPAn-6 groups tended to be similar and higher than in the AR-LA and AR-DPAn-6 groups. The levels of 22:5n-6 tended to be higher only in the absence of dietary 22:6n-3. Adipose levels of 22:5n-6 was the only exception, as 22:5n-6 was significantly higher in AR-DHA+DPAn-6 than was observed in either the DAM or the AR-DHA group. There were no differences in 20:4n-6 levels within the tissues examined. In conclusion, 22:5n-6 replaces 22:6n-3 in the absence of 22:6n-3 only and does not appear to compete with 22:6n-3 in the presence of dietary 22:6n-3, suggesting that oils containing 22:5n-6 and 22:6n-3 may be a good dietary source of 22:6n-3.

Serum Phospholipid‐Fatty Acid Patterns and Antioxidant Status in Cervical Cancer Patients

This study was to examine the phospholipid-fatty acid (PL-FA) patterns, antioxidant status in patients with cervical intraepithelial neoplasia (CIN, n=32), invasive cervical cancer (ICC, n=23), and normal controls (n=41). While the EPA (C20:5ω3)+DHA (C22:6ω3)/linolenic acid (C18:3ω3, LNA) ratio (ω3 product/ω3 precursor) showed a significantly lower value at the stage of CIN (p<.0001), arachidonic acid (C20:4ω6, AA)/linoleic acid (C18:2ω6, LA) ratio (ω6 product/ω6 precursor) tended to be higher in patients (p=0.0682). In ω6 series fatty acids, there were consistent trends that desaturation indices were higher and elongation indices were lower in both CIN and ICC than in control. The level of malondialdehyde (MDA) was significantly higher in ICC than in control and CIN. The value of total antioxidant performance (TAP) was significantly lower in CIN. These findings may be related to the possibility of oxidative injury in patients. In conclusion, although these changes have limitations to define causal-effect relationship between the PL-FA patterns and disease outcomes, the significant changes in fatty acid patterns and antioxidant status observed in this study suggest that those may have roles in cervical carcinogenesis.

Pro-oxidant effect of dehydroepiandrosterone in rats is mediated by PPAR activation

DHEA-treatment exerts a dual effect, prooxidant or antioxidant, depending on the dosage and, therefore, on the tissue concentration reached. In agreement with previous studies showing a prooxidant effect of DHEA, here we show that pharmacological doses of DHEA produce increased H 2O 2 levels and a marked reduction of GSH content in rat liver. DHEA, also increases both catalase (by 30%) and cytochrome-C-reductase (by 30%) activities in the liver cytosol. The effectiveness of the state of increased oxidative stress is also documented by changes in fatty acid pattern of the microsomal membranes. Moreover, DHEA, at high doses, enhances β-oxidation, as demonstrated by an increase of acyl-CoA-oxidase activity and of cytochrome P450 4A content, confirming that it acts as a PPARs inducer. Both PPARs induction and proxidant effects completely disappear when DHEA is administered at lower doses. Seven days treatment (4 or 10 mg) is unable to affect either levels of proxidant species and of antioxidant molecules, or cytochrome P450 4A content and β-oxidation. Prolonged DHEA treatment (4 mg/day) for three weeks not only is unable to affect PPARs activation and β-oxidation, but it also exerts a protective effect against ADP/Fe 2+ induced lipid peroxidation. This latter result confirms the antioxidant effects of DHEA at low doses, as already previously documented.

Effect of culture conditions on the lipid composition of Phytophthora infestans

Summary Phytophthora infestans is one of the most important of all plant pathogens and there is a demand for its more effective control. One target area for pesticides is lipid metabolism. To provide background information for studies with pesticides, we examined the lipids of P. infestans and how their composition is altered by culture conditions. Phytophthora infestans was grown in a pea‐broth and three different minimal media. Acyl lipids were extracted, separated by thin‐layer chromatography, identified and quantified. Total fatty acid patterns and those in individual lipid classes were measured by gas–liquid chromatography. Major polar lipids were the phosphoglycerides, phosphatidylcholine &gt; phosphatidylethanolamine &gt; phosphatidylinositol. The proportion of total polar lipids was reduced in minimal media. The similar fatty acid patterns of phosphatidylcholine and phosphatidylethanolamine were consistent with their metabolic relationship. Phytophthora infestans contained significant amounts of 22C unsaturated fatty acids, in addition to common fungal or oomycete fatty acids. Growth on minimal media caused changes in fatty acid patterns with increases in palmitate and linoleate and decreases in oleate being most obvious. Particular changes were also associated with the specific fatty acid patterns of individual lipids. The changes found in total fatty acids and in the acyl profiles of individual lipids suggest that desaturase activities are altered by growth conditions. These results and the greater proportions of storage triacylglycerol in minimal media agree with data for some other lower plants or fungi.

The rebound of lipoproteins after LDL-apheresis. Effects on chemical composition and LDL-oxidizability

The changes in low density lipoprotein (LDL) composition and oxidizability after LDL-apheresis (LA) using dextran sulfate cellulose columns were evaluated in 12 hypercholesterolemic men (mean±S.D. total cholesterol (TC) 9.7±1.8 mmol/l). After 10–20 months on biweekly LA combined with simvastatin 40 mg per day immediate pre-apheresis levels of TC, LDL-cholesterol, and apolipoprotein B were decreased to 5.3±1.3 mmol/l, 3.3±1.2 mmol/l, and 1.6±0.4 g/l, respectively, whereas apheresis induced mean acute reductions of 61, 78, and 76%, respectively. Measurements of copper-induced LDL-oxidizability in vitro showed an increased resistance against oxidation after LA until day 3 post-treatment: lag time (min) (day 0 (before LA) versus day 1 (post-LA)) 112±27 versus 130±26 ( P=0.001), maximal rate of diene production (nmol/min per mg LDL) 11.1±2.7 versus 9.1±2.1 ( P=0.001), and time to maximal diene production (min) 186±39 versus 209±35 ( P=0.001). Analysis of the chemical composition of LDL revealed a 25% ( P<0.001) reduced content of cholesteryl esters and a decrease of the cholesterol to protein ratio of 1.20±0.25 to 0.70±0.22 ( P<0.001) through the 3rd day post-LA. Linoleic acid and arachidonic acid content of LDL decreased 11 and 18%, respectively, at the expense of palmitic acid. Vitamin E levels (mg/l) were significantly lowered due to reduction of the lipoprotein pool by apheresis; however, vitamin E content of LDL did not change in the days after apheresis when expressed per g protein or per μmol linoleic acid. The changes in fatty acid pattern were strongly associated with changes in LDL-oxidizability indices ( P≤0.01). Thus, LA effectively decreased LDL pool size, inducing the presence of less buoyant lipoproteins, which were less susceptible to in vitro oxidation. This was not explained by changes in vitamin E levels, but by short-term changes in the fatty acids composition.

Peroxidation of lipid emulsions: effects of changes in fatty acid pattern and α-tocopherol content on the sensitivity to peroxidative damage

Peroxidation of lipid emulsions: effects of changes in fatty acid pattern and α-tocopherol content on the sensitivity to peroxidative damage

A function for the vitamin E metabolite α-tocopherol quinone as an essential enzyme cofactor for the mitochondrial fatty acid desaturases

A critical analysis of the changes in fatty acid patterns and their metabolism elicited by vitamin E deficiency leads to the proposal that a major role of dietary RRR-α-tocopherol (α-TOC) is as an enzymatic precursor of α-tocopherolquinone (α-TQ) whose semiquinone radical functions as an essential enzyme cofactor for the fatty acid desaturases of the recently elucidated carnitine-dependent, channeled, mitochondrial desaturation-elongation pathway; a detailed mechanism for its function is proposed. Pathophysiological states produced by vitamin E deficiency and α-TOC transfer protein defects, such as ataxia, myopathy, retinopathy, and sterility are proposed to develop from the effects of impaired α-TQ-dependent desaturases and the resulting deficiency of their polyenoic fatty acid products.

Plasma Cholesterol Ester Fatty Acids: A New Biochemical Abnormality in Obstructive Jaundice

Changes in fatty acid patterns may explain many of the observed abnormalities found in obstructive jaundice. This study looked at fatty acids in plasma cholesterol esters, in a group of patients with obstructive jaundice and a matched group of controls. Significant abnormalities were demonstrated, most importantly a fall in essential fatty acids, in the jaundiced group. Overall the saturation of this fraction, as assessed by double bond index, rose. The essential fatty acids are important as factors in membrane function and as precursors of eicosanoids. The abnormalities found in this study provide further evidence of the significance of EFA in patients with obstructive jaundice.

Interactive effects of dietary ( n − 3) polyunsaturated fatty acids and chronic ethanol intoxication on synaptic membrane lipid composition and fluidity in rats

The influence of dietary polyunsaturated fatty acids on fatty acid composition, cholesterol and phospholipid content as well as 'fluidity' (assessed by fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) probes) of brain synaptic plasma membranes (SPM) and their interactions with chronic ethanol effects were studied in rats fed for two generations with diets either devoid of (n-3) fatty acids (sunflower oil diet), rich in alpha-linolenic acid (soya oil diet) or in long chain (n-3) fatty acids (sunflower + cod liver oil diet). Results were compared with rats fed standard lab chow. Sunflower oil led to an increase in the (n-6)/(n-3) ratio in the membranes with an increase of the 'fluidity' at membrane apolar level; sunflower + cod liver oil decreased the (n-6)/(n-3) ratio without affecting membrane 'fluidity' while no difference was seen between the SPM of rats fed soya oil and standard diet. After 3 weeks alcohol intoxication in rat fed the standard diet: oleic alpha-linoleic acids and cholesterol levels were increased, arachidonic acid and the double bond index/saturated fatty acids were decreased and there was a decrease of 'fluidity' in the lipid core of the SPM. Soya oil almost totally abolished these usually observed changes in the SPM fatty acids composition but increased oleic acid and cholesterol without any change in fluidity. Sunflower oil led to the same general alterations of fatty acid as seen with standard diet but to a greater extent, with decrease of the 'fluidity" at the apolar level and in the region probed by TMA-DPH. When sunflower oil was supplemented with cod liver oil, oleic and alpha-linoleic acids were increased while the 'fluidity' of the apolar core of SPM was decreased. So, the small changes in fatty acid pattern seem able to modulate neural properties i.e. the responses to a neurotoxic like ethanol. A structurally specific role of PUFA is demonstrated by the pernicious effects of the alpha-linolenic acid deficient diet which are not totally prevented by the supply of long chain (n-3) PUFA.

Effects of linoleic and gamma-linolenic acids (efamol evening primrose oil) on fatty acid-binding proteins of rat liver

We have studied the effects of Efamol evening primrose oil (EPO) on fatty acid-binding proteins (L-FABP) of rat liver. EPO contains 72% cis-linoleic acid and 9% cis-gamma linolenic acid. EPO has been clinically used for treatment of a number of diseases in humans and animals. EPO is also known to lower cholesterol level in humans and animals. Feeding of an EPO supplemented diet to rats (n = 9) for 2 months decreases the oleate binding capacity of purified L-FABP of rat liver whereas the palmitate binding activity was increased by 38%. However, EPO feeding did not alter the L-FABP concentrations significantly as measured by using the fluorescence fatty acid probe, dansylamino undecanoic acid. Endogenous fatty acid analysis of L-FABPs revealed significant qualitative and quantitative changes in fatty acid pattern after EPO feeding. EPO feeding decreased the endogenous palmitate level by 53% and oleate level by 64% in L-FABPs and also EPO feeding decreased the total endogenous fatty acid content from 62 nanomole per mg of protein to 42 nanomole per mg of L-FABP (n = 3).

Changes in Fatty Acid Composition of Cervical Mucus Lecithin during Pregnancy

The fatty acid composition in cervical mucus was determined in 37 pregnant and 17 nonpregnant women using gas liquid chromatography. In both groups palmitic acid (16:0) and oleic acid (18:1) were the predominant acids comprising more than half of the total amount. Compared to nonpregnant controls, pregnant women had markedly elevated levels of oleic acid (18:1), while mean levels of myristic acid (14:0) and stearic acid (18:0) were significantly lower. These pregnancy-induced changes in fatty acid pattern could not be ascribed to the increased viscosity of cervical mucus. Only minor differences in fatty acid pattern were found between women in first trimester and at term. In contrast to nonpregnant controls, a significant negative correlation between levels of myristic acid (14:0) and docosahexaenoic acid (22:6) was found in pregnant women, indicating a redistribution of these two fatty acids during pregnancy. The present study demonstrates that pregnancy alters the fatty acid composition of cervical mucus lecithin, and that the characteristic changes are present before the 10th gestational week.

Plasma fatty acid composition in patients with ileal dysfunction.

Chemical signs of essential fatty acid deficiency (EFD) were studied in 31 patients who has undergone an ileal resection on an average 7 years earlier by determining fatty acid composition in serum lipids. The subjects were divided into two groups in accordance with the presence (greater than 7 g/day) or absence (less than 7 g/day) of fat malabsorption. The two groups were matched for age, nutritional status, and essential fatty acid intake, but the patients with steatorrhea had higher levels of fecal bile acids and serum triglycerides and lower levels of serum cholesterol than those without steatorrhea. The contents of linoleic acid (LA; 18:2,n-6), the sum of n-6 polyunsaturated fatty acids, and eicosapentaenoic acid levels were lower, whereas those of the C 14-18 saturated and monoenoic fatty acids and eicosatrienoic fatty acid (ETA; 20:3,n-9), a characteristic fatty acid of EFD, were higher in the serum lipids of the patients with fat malabsorption. The LA of cholesterol esters, the ETA of phospholipids, and the ETA to arachidonic acid ratio of phospholipids were closely correlated with the amount of fecal fat, less significantly with the composition of dietary fat or the length of excluded intestine, and not at all with relative body weight or the amount of fecal bile acids. Changes in fatty acid patterns, considered characteristic of EFD, were found for almost a third of the patients with fat malabsorption; yet no clinical evidence of EFD was documented. Thus, the results demonstrate that chemical signs of EFD are common in patients with fat malabsorption after gut resections despite the good nutritional status. The findings suggest that, for preventive purposes, patients with gut resections should increase their dietary intake of polyunsaturated fatty acids in proportion to the amount of fecal fat.

Membrane lipid changes in organic solvent tolerant neural cells.

Although, organic solvents are known to interact with neural membranes and to possess acute anesthetic properties, very little is known about the chronic effects of organic solvents on neural membranes. In the present study lipid compositional changes were examined after chronic exposure to the chlorinated organic solvents, trichloroethylene (TCE) and perchloroethylene (PCE). Animals were exposed continuously in inhalation chambers. Each experimental group had its own control group exposed simultaneously to air under identical conditions. Exposure to these organic solvents had only minor effects on lipid class composition. A tendency towards a decreased cholesterol to phospholipid ratio was observed, whereas the content of cerebrosides was unaffected. However, the proportions of the polyunsaturated fatty acids of ethanolaminephosphoglyceride (EPG) was consistently changed after exposure to either of these solvents for three months at (320 ppm). After longer exposure periods such alterations were observed at even lower solvent concentrations. This change in fatty acid pattern was characterized by an increase in linolenic acid derived fatty acids, with a concomitant decrease in fatty acids of the linolenic acid family. These changes may be an effort to compensate for the increased hydrophobic volume of membranes induced by dissolved solvent molecules. This compensation could be achieved by insertion of less coned lipid components into the membrane. The observed decrease in cholesterol to phospholipid ratio and the increase in the less saturated linoleic acid derived fatty acids could serve this function. Another possibility could be that chlorinated organic solvents interfere with the protein structure of desaturases, resulting in an alteration in the speed of desaturation and a changed fatty acid composition.

Fatty acids in plasma and red cell membranes of normal and hyperlipoproteinemic subjects

Fatty acids have been implicated in the pathogenesis of thromboatherosclerosis. The purpose of this investigation was to determine if the increase in the plasma concentration of total cholesterol (TC) and/or triglycerides observed in hyperlipoproteinemias leads to changes in fatty acid patterns, namely serum free fatty acids, red blood cell membrane phosphatidylcholine, high density lipoprotein phosphatidylcholine (HDL-P) and HDL-cholesterol esters. The C18:1/C18:2 ratio in each lipid fraction was calculated and correlated with the values of TC and triglyceride concentrations, TC/HDL-C and apo A 1/apo B ratios. According to the results of this experiment, we may conclude that each of the studied lipid fractions has a characteristic fatty acid composition. These fatty acid patterns are apparently unaffected by the increase in serum cholesterol and/or triglyceride concentrations observed in the hyperlipoproteinemic subjects. No correlation was observed between C18:1/C18:2 ratio from each lipid fraction. Finally, no correlation was detected between the C18:1/C18:2 ratio and the values of total serum cholesterol, triglyceride concentrations, CT/HDL-C and apo A 1/apo B ratios.

Excessive Intake of 13-cis Retinoic Acid and Fatty Acid Composition of Tissues

The effects of feeding an excess of 13-cis retinoic acid on the fatty acid composition of tissues were studied. Groups of male, weanling, Sprague-Dawley rats were fed diets containing 0, 100 and 300 mg 13-cis retinoic acid per kilogram diet. Rats were killed 4 weeks after feeding the diets, and the fatty acid composition of total lipids in plasma, liver, kidney, heart and lung was determined. Changes in fatty acid patterns were observed primarily in plasma and liver. The proportions of 16:1, 18:1 and 20:3ω6 were generally higher, whereas those of 20:4 were lower. The fatty acid composition of kidney, heart and lung lipids was not appreciably changed. The results on fatty acid changes in liver suggest that 13-cis retinoic acid may be modifying the activities of desaturating enzymes.

Effects of dietary fat on lipid composition of serum and erythrocytes of the swine and in vitro incorporation of fatty acids into erythrocyte membranes.

Changes in fatty acid patterns of lipids in serum and erythrocytes in-duced by dietary fats and in vitro incorporation of fatty acids into ery-throcyte membranes were investigated with pigs. On feeding various diets, it was found that fatty acid composition of serum and erythrocytes could be modified and altered toward the fatty acid pattern of the diet. In vitro, the incorporation of labeled fatty acids into erythrocyte mem-branes was accelerated by the addition of cofactors such as lysolecithin, CoA and ATP. Dietary fats also had certain effects on the incorporation of fatty acids into erythrocyte membranes. Erythrocytes, collected from the blood of pigs fed corn oil, incorporated and also released more labeled linoleate than those of pigs fed hydrogenated soybean oil. Palmitic acid was more slowly incorporated into erythrocyte membranes than linoleic acid in the pigs fed both a commercial chow and scheduled meals, indicating selective esterification of fatty acids in the erythrocyte membranes.