Role of phospholipids in early ontogenesis of Arctic-Boreal species <Emphasis Type="Italic">Leptoclinus maculatus</Emphasis> (Stichaeidae)

The content of total phospholipids and their classes (phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine, sphingomyelin) of muscles (flesh) and lipid sac of different developmental stages of young fish the daubed shanny, Leptoclinus maculatus from Kongsfjord (Svalbard, Norway) in winter was studied. The content of phospholipids in flesh decreases with age on account of phosphatidylcholine and phosphatidylethanolamine that probably related to their role in morphogenesis during differentiation of tissues and organs. The content of phospholipids is lower than reserve lipids in the lipid sac. The level of phospholipids in the lipid sac compared to flesh increases with age of fish reaching the maximum in benthic juveniles. Variations of minor phospholipids content of young fish of the daubed shanny indicate their participation in biochemical mechanisms of adaptation realizing in specific and varying Arctic conditions.     

Lipid composition of copepodite stages and adult females of Calanus glacialis in Arctic waters of the Barents Sea

Summary The composition of lipid classes and their component fatty acid are described for copepodite stages III, IV, V, and adult females of Calanus glacialis sampled from Arctic waters of the Barents Sea during summer. Was esters were the principal component of the lipid in all copepodite stages examined, averaging 73% over all the stages. The proportion of triacylglycerols varied from 1.5% to 10.5% of total lipid among copepodite stages. The lipids of adult females contained lower levels of wax esters and higher levels of triacylglycerols than copepodite stages III, IV and V. Fatty alcohols of wax esters from copepods sampled in June and July were dominated by 20:1 (n-9) and 22:1 (n-11) alcohols with the proportion of 20:1 (n-9) increasing from stages III to adult female. 14:0 and 16:0 alcohols were the principal fatty alcohols of wax esters of a sample comprising mainly of copepodites stage III taken in August. 16:1 (n-7), 20:1 (n-9) and 20:5 (n-3) were the major fatty acids in the was esters of animals captured in June and July whereas 18:1 (n-9) predominated in the August sample. The polar lipids of the copepodite stage III from August also contained lower levels of polyunsaturated fatty acids than from all stages of copepods from June and July. The data are discussed in relation to life cycle strategies and trophic aspects of Calanus glacialis in the Arctic pelagic community of the Barents Sea.     

Studies on furan fatty acids of salmon roe phospholipids

Mature salmon roe lipids were found to consist of triacylglycerols (63%), phospholipids (30%), sterols (4.2%), steryl esters (0.7%), and other minor components. In the steryl esters and phospholipids, furan fatty acids were detected instead of the triacylglycerols of the testes lipids in male fish. The representative 12,15-epoxy-13,14-dimethyleicosa-12,14-dienoic acid (F6) amounted to 3.8% and 0.6% of the total fatty acids in each fraction, respectively. However, the absolute amount of the acid in the phospholipid was much more than that contained in the steryl esters. The characteristic distribution of the furan acids found in the phospholipids was common to the steryl esters in the liver. Large amounts of furan acids were contained in phosphatidylcholine (PC) rather than in phosphatidylethanolamine. For positional analysis of furan fatty acids in PC, furan-containing species in the molecule were concentrated fourteenfold by using selective hydrogenation and repeated silica gel column chromatography. A series of furan fatty acids in PC was found to be exclusively linked to the sn-1 position. The amount of the acids in the roe exclusively linked to the sn-1 position. The amount of the acids in the roe phospholipids was comparable with that in the testes triacylglycerols. The physiological roles of furan fatty acids are discussed.     

Lipids and fatty acids in muscle, liver and skin of three edible fish from the Senegalese coast: Sardinella maderensis, Sardinella aurita and Cephalopholis taeniops

Lipid content and fatty acid composition were determined in three species of edible fish caught in Senegalese waters during the upwelling season (January, 1993). Sardinella maderensis and Sardinella aurita are fat fish containing more than 5% (fresh wt.) of lipids, whereas Cephalopholis taeniops is a lean fish with approximately 1% of lipids. Skin, liver and muscle were studied for each fish species. About 40 fatty acids were identified by GC and GC/MS as methyl esters and N-acyl pyrrolidides. Palmitic acid was the main acid in the muscle and skin of all samples studied (20-33% of total fatty acids). Oleic acid was the main fatty acid in the liver of S. maderensis (27.2%+/-0.1) and S. aurita (44.7%+/-0.1). Arachidonic acid was a minor component in all samples. The flesh (muscle) of the three fish species contained high concentrations of omega3 polyunsaturated fatty acids (PUFA), ranging from 16.0 to 29.1% and including 20:5 omega3 (eicosapentaenoic acid, EPA) and 22:6 omega3 (docosahexaenoic acid, DHA) acids as major components. These two acids together accounted for 24.7%+/-0.1 and 12.9%+/-0.1 of total acids in the skin of S. maderensis and S. aurita, respectively. The percentages of PUFA found in the fish studied were very similar to those in fish used commercially as sources of PUFA. Muscle sterols, which accounted for 9-11% of total lipids, consisted mainly of cholesterol (up to 97% of total sterols).     

Selectivity in mobilisation of stored fatty acids by maturing cod, Gadus morrhua L

Lipids, proteins and carbohydrates diminish in the liver and muscle of cod when (a) food is inadequate or (b) the gonads are maturing. The results reported in this paper appear to show that the mobilisation of the lipids differs according to whether the need is just for energy (simple starvation) or for building up gonads. Two groups of fish from the same catch were starved. In one, the gonads were developing, while in the other the gonads had been surgically removed. Significantly more of the fatty acid C22:6 was mobilised from the liver lipids in the group with developing gonads, this fatty acid being present in the greatest amount in the gonads of either sex. The fatty acid C18:1 is also important in the gonads, and this was also preferentially removed from all the livers of maturing-starving fish when compared with gonadectomised-starving, though here the effect was not statistically significant. Some discrimination therefore appears to be exercised when hepatic lipids are removed for gonad development. No selectivity was observed in the mobilisation of fatty acids from the muscle.     

Effects of dietary linseed,evening primrose or fish oils on fatty acid and prostaglandin E2 contents in the rat livers and 7,12-dimethylbenz[a]anthracene-induced tumours

We examined the influence of diets supplemented with fish and vegetable oils on fatty acid and prostaglandin E₂ (PGE₂) contents in livers of non-7,12-dimethylbenz[a]anthracene (DMBA)- and DMBA-treated rats, and in DMBA-induced tumours. Decreased concentrations of saturated fatty acids and increased unsaturated fatty acid levels were observed in liver phospholipids of rats fed these oils. There was a marked difference in the concentrations of fatty acids found in the tumours and those present in liver lipids. Oleic acid was the main unsaturated fatty acid found in the tumour tissue. Both liver and tumour PGE₂ contents were clearly correlated to the diet. The PGE₂ concentrations were decreased in livers and tumours of rats fed fish (FO) and linseed oils (LO).     

Effect of sex and bezafibrate on incorporation of blood borne palmitate into lipids of rat liver nuclei

The aim of the present study was to investigate whether lipid metabolism in the nuclei is affected by changes in the metabolism of free fatty acids in the liver. The experiments were carried out on 3 groups of rats: 1 - control-male, 2 - female, and 3 - male, treated with bezafibrate (a peroxisome proliferator). The rats received ¹⁴C-palmitic acid intravenously. Thirty min later liver samples and blood from the abdominal aorta were taken. The liver nuclei were isolated in sucrose gradient. Lipids were extracted from the nuclei and the liver homogenate and subsequently separated into the following fractions: phospholipids, mono-, di- and triacylglycerols, free fatty acids, cholesterol and cholesterol esters. The radioactivity of each fraction was counted. Furthermore, the content of free fatty acids and the fatty acid binding proteins was measured. It was found that radioactivity was present in each lipid fraction obtained from the liver homogenate and from the nuclei. In the female group, the total radioactivity of lipids in the liver homogenate was lower, whereas in the nuclei it was higher in comparison to the male group. The reduction in the radioactivity in the liver was mostly accounted for by decreased radioactivity in the fraction of triacylglycerols and phospholipids. In the nuclei, the radioactivity of the fraction of phospholipids, free fatty acids and diacylglycerols was elevated. Bezafibrate did not affect the total radioactivity of lipids in the liver and reduced it in the nuclei. In the liver, the drug increased radioactivity mostly in the fraction of phospholipids and reduced it mainly in the fraction of triacylglycerols. In the nuclei, the radioactivity of each lipid fraction examined was reduced. The content of the fraction of free fatty acids in the liver and in the nuclei in the female and in the bezafibrate-treated groups did not differ from the respective value in the control group. The content of fatty acid binding proteins in the nuclei of the female and bezafibrate-treated groups increased in parallel to the elevation in their content in the cytosol. It is concluded that the female sex hormones and bezafibrate influence the transport of selected lipids into the nuclei. The effects seem to be a consequence of the action of these factors directly on the nucleus.     

Lipid content and composition of the Antarctic lamellibranch, Laternula elliptica (King & Broderip) (Anomalodesmata: Laternulidae), in King George Island during an austral summer

Total lipid content, lipid classes and fatty acid composition were studied in various tissues of the Antarctic clam Laternula elliptica in an early austral summer. A histological examination of the gonads revealed that most of the clams examined were spawning or ready to spawn. Lipid content was highest in gills (14.9% of tissue dry weight), followed by gonads (10.9%) and digestive glands (9.9%), and averaged 8.2% for the soft tissues. The overall lipid contents were relatively low compared to temperate bivalves at a similar reproductive stage. Lipid class composition in the total lipid of L. elliptica was quite similar to those of most marine bivalves at lower latitudes, being dominated by triacylglycerols (19.3–41.4% of total lipids) and phospholipids (18.9–28.3%) in most of the organs. Large amounts of triacylglycerol deposits in non-reproductive tissues, particularly in siphon and gill, indicate a potential role of lipid as maintenance energy reserve, although the low lipid contents suggest that lipid may not serve as an energy reserve for any food-limited periods. Fatty acid composition in L. elliptica was also typical of marine bivalves with predominance of 16:0 (26%) and 20:5n-3 (18%) acids. Total fatty acids from the soft tissues showed a moderate level of unsaturation (50.6%), and about 35% of the total fatty acids were polyunsaturated. These values were not significantly different from, or even lower than those of marine bivalves in warmer waters. However, the content of 20:5n-3 (18.2% of total fatty acids), which dominated n-3 polyunsaturated fatty acids, was similar to those reported for other marine bivalve species in temperate waters. The fatty acid composition of L. elliptica reflected dietary input of some microalgal species. The nanoflagellates Cryptomonas spp., which were reportedly rich in 16:0, 18:3n-3 and 20:5n-3, predominated in the water column during the present investigation. Accepted: 19 June 1999     

Effect of sex and bezafibrate on incorporation of blood borne palmitate into lipids of rat liver nuclei

The aim of the present study was to investigate whether lipid metabolism in the nuclei is affected by changes in the metabolism of free fatty acids in the liver. The experiments were carried out on 3 groups of rats: 1 - control-male, 2 - female, and 3 - male, treated with bezafibrate (a peroxisome proliferator). The rats received 14C-palmitic acid intravenously. Thirty min later liver samples and blood from the abdominal aorta were taken. The liver nuclei were isolated in sucrose gradient. Lipids were extracted from the nuclei and the liver homogenate and subsequently separated into the following fractions: phospholipids, mono, di- and triacylglycerols, free fatty acids, cholesterol and cholesterol esters. The radioactivity of each fraction was counted. Furthermore, the content of free fatty acids and the fatty acid binding proteins was measured. It was found that radioactivity was present in each lipid fraction obtained from the liver homogenate and from the nuclei. In the female group, the total radioactivity of lipids in the liver homogenate was lower, whereas in the nuclei it was higher in comparison to the male group. The reduction in the radioactivity in the liver was mostly accounted for by decreased radioactivity in the fraction oftriacylglycerols and phospholipids. In the nuclei, the radioactivity of the fraction of phospholipids, free fatty acids and diacylglycerols was elevated. Bezafibrate did not affect the total radioactivity of lipids in the liver and reduced it in the nuclei. In the liver, the drug increased radioactivity mostly in the fraction of phospholipids and reduced it mainly in the fraction of triacylglycerols. In the nuclei, the radioactivity of each lipid fraction examined was reduced. The content of the fraction of free fatty acids in the liver and in the nuclei in the female and in the bezafibrate-treated groups did not differ from the respective value in the control group. The content of fatty acid binding proteins in the nuclei of the female and bezafibrate-treated groups increased in parallel to the elevation in their content in the cytosol. It is concluded that the female sex hormones and bezafibrate influence the transport of selected lipids into the nuclei. The effects seem to be a consequence of the action of these factors directly on the nucleus.     

Metabolism of Hydrocarbons in Microorganisms

The fatty acid composition of the lipid of yellowfin tuna (Thunnus albacares) caught in two different localities, Philippine Sea (a tropical zone) and the Pacific coast area of Japan (a temperate zone) is described. The total lipids of various organs (dorsal ordinary muscle, ventral ordinary muscle, dark muscle, liver, heart, pyloric cecum, and orbital region) and of the stomach contents were extracted, and the fatty acid comosition was analyzed by gas-liquid chromatography (GLC).

Docosahexaenoic acid (DHA; 22:6n-3) was the major unsaturated fatty acid in the lipid of all organs in the specimens examined from both localities, the mean DHA content accounting for more than 25% (mean ± S.D. of 26.9 ±5.7%) of the total fatty acids. This value is markedly different from the fatty acid profile of other fish species, because, in general, the fatty acid composition of other species is variable and the DHA content is less than 20% of total fatty acids.

Although the mean DHA content of the total fatty acids in the lipid of yellowfin tuna caught in the tropical and temperate zones was markedly higher than that in other fish species, there was a small difference between that in the northern samples (temperate waters, 30.5 ±6.1%) and the southern samples (tropical waters, 25.9 ± 5.2%). It is suggested that this difference may be due to environmental effects, e.g., the fatty acid composition of the lipids of prey organisms, because there is also a small difference between the mean DHA content of northern prey fish (22.7 ±6.1%) and that of southern prey fish (19.2 ±4.0%).     

Percentage recovery of free fatty acids from bovine muscle lipids by nonchromatographic techniques

The inability of silicic acid to completely separate the neutral lipids from phospholipids has been reported by several investigators (1,2). Hornstein et al. (3) increased the polarity of the solvent system and reported a clean separation of the phospholipid fraction by adsorption on activated silicic acid. Studies on bovine lipids by Hood and Allen (2) utilized acid-washed Florisil to separate the lipid fractions claiming that silicic acid incompletely separates the free fatty acids from the phospholipids. Work performed in this laboratory (4) on bovine lipids confirmed that phospholipids could be effectively separated from free fatty acids by adsorption on silicic acid by incorporating the solvent system described by Hornstein et al. (3). The liquid-liquid partition procedure of Hamilton and McDonald (5) was also found to be sensitive enough to partition the extremely small amount of free fatty acids from the esterified fatty acids. This paper provides evidence for the effectiveness of these methods in separating the frec fatty acids by incorporating an internal standard [1-¹⁴C]palmitic acid.     

The occurrence of arachidonic acid in Triatoma infestans

1. Gas-liquid chromatography and mass spectrometry were used to verify the presence of arachidonic acid (20:4 omega 6) in adult male and female organs of the blood-suckling bug Triatoma infestans. Fat body, gonad and head lipids were analyzed. 2. Male gonads contained the highest percentage of phospholipids and the highest percentage of arachidonic acid. 3. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine and sphingomyelin were isolated from gonads and heads of sexed insects and the fatty acid composition analyzed. 4. All the phospholipids analyzed contained relevant percentages of linoleic acid and fair percentages of arachidonic acid, except for sphingomyelin where no 20:4 omega 6 acid was found. 5. However, arachidonic acid was specifically incorporated in phosphatidylinositol since this phospholipid contained very large percentages of the acid. 6. In male gonads, phosphatidylcholine also contained a similar high percentage of the acid. Arachidonic acid is apparently incorporated, selectively, into these lipids from the blood of the host.     

Lipid and fatty acid composition of the fat body during the female reproductive cycle of Labidura riparia (Insecta Dermaptera)

During the reproductive cycle of the female Labidura riparia, cytological observations show cyclical modifications of lipid droplets in the periovarian adipocyte. Fat body lipids and their constitutive fatty acids are analyzed. The lipids are predominantly triacylglycerols, which increase after adult ecdysis during vitellogenic and non-vitellogenic periods. Small amounts of diacylglycerols and phospholipids are found. Diacylglycerols increase during vitellogenesis and decrease during the non-vitellogenic period. Cytological modifications of lipid droplets are probably related to diacylglycerol fluctuations. Gas-liquid chromatography of fatty acid methyl esters shows oleic acid to be the predominant fatty acid in total lipids and triacylglycerols; unsaturated acids are approximately twice as abundant as saturated acids all along the reproductive cycle. Fatty acid composition of diacylglycerols and phospholipids differs from triacylglycerols and total lipids composition. Palmitic, stearic, oleic and linoleic acids represent the major fatty acids; their relative amounts vary during the different periods of the reproductive cycle. The correlations between fat body lipid changes and ovarian development were discussed and compared with observations made on other insect species. Accepted: 23 April 1997     

Lipids in plant tissue cultures. VI. Effect of temperature on the lipids of Brassica napus and Tropaeolum majus cultures

The lipid contents of callus cultures of rape (Brassica napus) and nasturtium (Tropaeolum majus) increase in response to decreasing the temperature, though to different degree. Irrespective of the incubation temperature the lipids in cultures of both plants contain as predominant classes steryl glycosides, esterified steryl glycosides, sterols, steryl esters and fatty acids and, as minor constituents, various proportions of triacylglycerols, phospholipids and several unidentified fractions.The ratio of phospholipids to triacylglycerols as well as the ratio of diacylglycerophosphorylethanolamines to dicylglycerophosphorylcholines increase with time both in rape cultures incubated at 30°C and in those kept at 5°C.The lipids in rape and nasturtium cultures grown at 30°C contain smaller proportions of polyunsaturated fatty acids than the lipids in cultures incubated at 5°C. Erucic acid, the major constituent fatty acid of the seed lipids, in both plants, occurs only in trace amounts in the lipids of callus cultures. In contrast, linoleic and linolenic acids, which occur only in traces in the seed lipids of nasturtium, are major constituent fatty acids in the lipids of callus cultures derived from seedlings of this plant.The levels of constituent polyunsaturated fatty acids in the diacylglycerophosphorylethanolamines and the diacylglycerophosphorylcholines increase with time whereas in the triacylglycerols only linolenic acid is slightly increased.     

Age‐Related Changes in Fatty Acids in Obese Offspring of Streptozotocin‐Induced Diabetic Rats

Objective: The long‐term effects of fetal hyperinsulinemia, time course of changes in liver and very‐low‐density lipoprotein (VLDL) lipid levels and fatty acid compositions were investigated in obese offspring of streptozotocin‐induced mildly diabetic rats. Research Methods and Procedures: Mild hyperglycemia in pregnant rats was induced by intraperitoneal injection of streptozotocin on day 5 of gestation. Control pregnant rats were injected with citrate buffer. Liver and VLDL lipids and fatty acids were analyzed in offspring at different ages. Results: At birth, obese pups had higher VLDL triglyceride levels, saturated fatty acids, and C20:4n‐6. They also had lower C18:2n‐6 proportions in VLDL triglycerides, phospholipids, and cholesteryl esters than controls pups. In 1‐month‐old male and female obese rats, VLDL and liver lipid amounts were similar to those in their respective controls; however, high levels of C18:2n‐6 and C20:4n‐6 were noted in liver and VLDL lipids. At the age of 2 months, liver and VLDL triglyceride levels were higher in obese females than in control females. Fatty acid abnormalities seen in obese rats included low C18:3n‐3 and high C22:6n‐3 proportions in liver triglycerides and phospholipids. At the age of 3 months, obese rats, both males and females, compared with control animals, had higher VLDL and hepatic lipids with reduced C20:4n‐6 levels and polyunsaturated/saturated fatty acids ratios in hepatic and VLDL triglycerides and phospholipids. Discussion: Fetal obesity, associated with alterations in VLDL lipid fatty acid composition, represents an important risk factor for adult obesity and diabetes.     

Fatty acid and lipid analysis of the house cricket,Acheta domesticus

The fatty acid content and composition of the house cricket Acheta domesticus have been investigated in entire insects at different developmental stages and in selected organs of male and female adults. We have also determined the fatty acid composition of the various lipid classes within extracts of the organs of adult female insects. Fatty acids were analysed by capillary gas chromatography or mass spectrometry as their methyl esters (FAMEs) after direct transesterification of insect material or separated lipid classes.The major esterified fatty acids in all extracts were palmitate (C_16:0), stearate (C_18:0), oleate (C_18:1) and linoleate (C_18:2). Levels of esterified fatty acid varied considerably between organs but the fatty acid compositions showed only small variations. The levels of polyunsaturated fatty acids of the C₁₈ series were considerably higher in phospholipid fractions than in other lipid classes. Triacylglycerols formed the major lipid class in ovaries, fat-body and newly-laid eggs, whereas diacylglycerols and phospholipid predominate in the haemolymph. Triacylglycerols, phospholipids, diacylglycerols and free fatty acids were all found in significant amounts in the gut tissue.     

Separation and detection of neutral lipids and free fatty acids in a liver extract by high-performance liquid chromatography

A relatively simple method to determine hepatic neutral lipids and free fatty acids by highperformance liquid chromatography is described. This method involves the preparation of a chloroform extract of the total liver lipids, followed by removal of the phospholipids by adsorption onto silicic acid and elution of neutral lipids and free fatty acids with 50% diethyl ether in hexane. This fraction is then subjected to liquid-solid chromatography with a solvent system of 2,2,4-trimethylpentane (isooctane):tetrahydrofuran:formic acid (90:10:0.5) and is detected by refractive index. Cholesterol esters, fatty acids, cholesterol, and diglycerides each elute as single peaks, easily quantitated by comparison to appropriate standards. Baseline separation of triglycerides from cholesterol esters is also achieved.     

Selective incorporation of n-3 and n-6 fatty acids in essential fatty acid deficient rats in response to short-term oil feeding

Essential fatty acid deficient male Sprague Dawley rats were fed for 7 days a fat-free semi-synthetic diet supplemented with 10% by weight of different oil supplements. The oil supplement was a mixture of olive, safflower and linseed oils prepared at different proportions so the dietary n-9/n-6/n-3 ratios were approximate 2/1/1, 1/2/1, 1/1/2, and 1/1/1. The fatty acid compositions of plasma and liver lipids were then examined. Our results show polyunsaturated n-6 and n-3 fatty acids were selectively incorporated into plasma and liver phospholipids, and also into plasma cholesteryl esters. A preferential incorporation of n-6 over n-3 fatty acids into plasma cholesteryl esters and phospholipids was also observed.     

Dietary Omega-3 Polyunsaturated Fatty Acids Alter the Fatty Acid Composition of Hepatic and Plasma Bioactive Lipids in C57BL/6 Mice: A Lipidomic Approach

Background

Omega (n)-3 polyunsaturated fatty acids (PUFA) are converted to bioactive lipid components that are important mediators in metabolic and physiological pathways; however, which bioactive compounds are metabolically active, and their mechanisms of action are still not clear. We investigated using lipidomic techniques, the effects of diets high in n-3 PUFA on the fatty acid composition of various bioactive lipids in plasma and liver.

Methodology and Principal Findings

Female C57BL/6 mice were fed semi-purified diets (20% w/w fat) containing varying amounts of n-3 PUFA before mating, during gestation and lactation, and until weaning. Male offspring were continued on their mothers’ diets for 16 weeks. Hepatic and plasma lipids were extracted in the presence of non-naturally occurring internal standards, and tandem electrospray ionization mass spectrometry methods were used to measure the fatty acyl compositions. There was no significant difference in total concentrations of phospholipids in both groups. However, there was a significantly higher concentration of eicosapentaenoic acid containing phosphatidylcholine (PC), lysophosphatidylcholine (LPC), and cholesteryl esters (CE) (p < 0.01) in the high n-3 PUFA group compared to the low n-3 PUFA group in both liver and plasma. Plasma and liver from the high n-3 PUFA group also had a higher concentration of free n-3 PUFA (p < 0.05). There were no significant differences in plasma concentrations of different fatty acyl species of phosphatidylethanolamine, triglycerides, sphingomyelin and ceramides.

Conclusions/Significance

Our findings reveal for the first time that a diet high in n-3 PUFA caused enrichment of n-3 PUFA in PC, LPC, CE and free fatty acids in the plasma and liver of C57BL/6 mice. PC, LPC, and unesterified free n-3 PUFA are important bioactive lipids, thus altering their fatty acyl composition will have important metabolic and physiological roles.     

Effect of fat free diet during the last week of pregnancy upon the linoleic and arachidonic acid content of fetal organ lipids and placenta lipids of the rat

Pregnant Wistar rats were fed a fatfree diet from day 16--22 of pregnancy. On day 22, the fatty acid components of cholesterol esters, triglycerides, free fatty acids and phospholipids of maternal (brain, muscle, serum, white adipose tissue, liver) and fetal (brain, carcass, serum, liver) tissues, including the placenta, were examined gaschromatographically for the participation of linoleic and arachidonic acid. In all fetal and maternal organs the linoleic acid levels in the fatty acid patterns were strongly reduced. The alterations nearly always involved all the lipid fractions of a tissue and were mostly equal within a tissue. The strongest decreases of linoleic acid occurred in the placenta, and the weakest, in the lipids of maternal muscle and maternal adipose tissue. The linoleic acid alterations were principally similar in fetal and the corresponding maternal tissues, while being less pronounced in case of maternal muscle. The participation of arachidonic acid in the fatty acid pattern is completely retained in the lipids of fetal organs, and is even enhanced in those of the placenta.