13C nuclear magnetic resonance spectroscopic analysis of the triacylglycerol composition ofBiota orientalis and carrot seed oil

¹³C nuclear magnetic resonance (NMR) spectroscopic analysis of the whole oil (triacylglycerols) ofBiota orientalis seeds confirms the presence of oleate [18:1(9Z)], linoleate [18:2(9Z, 12Z)], linolenate [18:3((9Z, 12Z, 15Z)], 20:3 (5Z, 11Z, 14Z), 20:4(5Z, 11Z, 14Z, 17Z), and saturated fatty acids in the acyl groups by comparing the observed carbon shifts with previously established shift data for model triacylglycerols. This technique shows that the saturated, 20:3 and 20:4 fatty acids are distributed mainly in the α-acyl positions, whereas oleate, linoleate, and linolenate are randomly acylated to the α- and β-positions of the glycerol “backbone”. Stereospecific hydrolysis of theBiota oil with pancreatic lipase, followed by chromatographic analysis of fatty esters, reveals the presence of trace amounts of 16:0(0.7%), 18:0(0.5%), 20:3 (0.4%), and 20:4 (1.3%) in the β-position of the glycerol “backbone”, which are undetectable by¹³C NMR technique on the whole oil. Semiquantitative assessment of the¹³C NMR signal intensities gives the relative percentages of the fatty acid distribution as: saturated 16:0, 18:0 (12.0% α-acyl), oleate (7.7% α-acyl 8.7% β-acyl), total linoleate and linolenate (31.7% α-acyl; 24.2% βacyl), total 20:3 and 20:4 (15.7% α-acyl). The¹³C NMR spectroscopic analysis of carrot seed oil identifies the presence of saturated (18:0), 18:1(6Z), 18:1(9Z), and 18:2(9Z, 12Z). The saturated fatty acid is found in the α-acyl positions. Semi-quantitative assessment of the signal intensities gives the relative percentages of the fatty acids as: 18:0 (4.5% α-acyl), 18:1(6Z) (49.6% α-acyl; 19.7% β-acyl), oleate (6.5% α-acyl; 8.6% β-acyl) and linoleate (5.2% α-acyl; 6.9% β-acyl).     

Perfluorodecanoic acid and lipid metabolism in the rat

Alterations in lipid metabolism were axamined in adult male Sprague-Dawley rats seven days after a single intraperitoneal injection of perfluorodecanoic acid (PFDA; 20, 40 or 80 mg/kg). Because PFDA treatment caused a dose-related reduction in feed intake, the response of vehicle-treated rats pair-fed to those receiving PFDA was monitored to distinguish direct effects of the perfluorinated fatty acid from those secondary to hypophagia. Carcass content of lipid phosphorus and free cholesterol decreased in dose-dependent fashion in both PFDA-treated and pair-fed rats. Carcass triacylglycerols diminished in a similar manner, yet PFDA-treated rats at each dose had a higher concentration of neutral acylglycerols than their vehicle-treated, pair-fed counterparts. In vehicle-treated, pair-fed rats at the 80 mg/kg dose level, lipid phosphorus and free cholesterol as a proportion of carcass fat increased, whereas the share of the triacyl-glycerols declined. Because of the higher concentration of triacylglycerols in the carcass of rats treated with 80 mg/kg PFDA, enrichment of lipid phosphorus and free cholesterol in carcass fat was less than in their pair-fed partners. The amount of lipid phosphorus and free cholesterol per hepatocyte was similar in both PFDA-treated rats and their pair-fed partners. Liver triacyl-glycerols were markedly increased in PFDA-treated rats. A similar but less extensive augmentary effect of PFDA on hepatic esterified cholesterol was found. Concentration of triacylglycerols in plasma was not elevated in PFDA-treated rats, in spite of hepatic accumulation of esterified compounds. Also, the plasma level of free fatty acids and 3-hydroxybutyrate was similar in all treatment groups, including those receiving PFDA. Thus, the administration of PFDA appears to divert fatty acids from oxidation toward esterification in the liver.     

Occurrence of 5c,8c,11c,15t-eicosatetraenoic acid and other unusual polyunsaturated fatty acids in rats fed partially hydrogenated calola oil

Uncommoncis andtrans fatty acids can be desaturated and elongated to produce unusual C₁₈ and C₂₀ polyunsaturated fatty acids in animal tissues. In the present study we examined the formation of such metabolites derived fromcis andtrans isomers of oleic and linoleic acids of partially hydrogenated vegetable oil origin in rats. For two months, aduut male rats were fed a partially hydrogenated canola oil diet containing moderately high levels oftrans fatty acids (9.6 energy%) and an adequate level of linoleic acid (1.46 energy%). Analysis of the phospholipid (PL) fatty acids of liver, heart, serum and brain showed no new C₁₈ polyunsaturated fatty acids, except for those uncommon 18∶2 isomers originating from the diet. However, minor levels (each <0.3% PL fatty acids) of six unusual C₂₀ polyunsaturated fatty acids were detected in the tissues examined, except in brain PL. Identification of their structures indicated that the dietary 9c,13t−18∶2 isomer, which is the majortrans polyunsaturated fatty acid in partially hydrogenated vegetable oils, was desaturated and elongated to 5c,8c,11c,15t−20∶4, possibly by the same pathway that is operative for linoleic acid. Furthermore, dietary 12c−18∶1 was converted to 8c,14c−20∶2 and 5c,8c,14c−20∶3; dietary 9c,12t−18∶2 metabolized to 11c,14t−20∶2 and 5c,8c,11c14t−20∶4, and dietary 9t,12c to 11t,14c−20∶2. These results suggested that of all the possible isomers of oleic and linoleic acids in partially hydrogenated vegetable oils, 12c−18∶1, 9c,13t−18∶2, 9c,12t−18∶2 and 9t,12c−18∶2 are the preferred substrates for desaturation and elongation in rats. However, their conversions to C₂₀ metabolites were not as efficient as that of oleic or linoleic acids.     

Effects of Pinus pinaster and Pinus koraiensis seed oil supplementation on lipoprotein metabolism in the rat

The aim of the present study was to assess the effect of vegetal oils obtained from Pinus pinaster and P. koraiensis seeds on plasma lipoprotein levels and apolipoprotein (apo) gene expression in rats. These oils contain two particular fatty acids of the Δ5-unsaturated polymethylene-interrupted fatty acid (Δ5-UPIFA) family: all-cis-5,9,12-18:3 (pinolenic) and/or all-cis-5,11,14-20:3 (sciadonic) acids. Rats were fed for 28 d a diet containing 5% (w/w) oil supplement. Two control diets were prepared to match the fatty acid composition of P. pinaster or P. koraiensis oils with the exception of Δ5-UPIFA, which were replaced by oleic acid. Pinus pinaster seed oil decreased serum triglycerides by 30% (P<0.02), very low density lipoprotein (VLDL)-triglycerides by 40% (P<0.01), and VLDL-cholesterol by 33% (P<0.03). Pinus koraiensis seed oil decreased serum triglycerides by 16% [not statistically significant (ns)] and VLDL-triglycerides by 21% (ns). Gel permeation chromatography and nondenaturating polyacrylamide gel electrophoresis showed a tendency of high density lipoprotein to shift toward larger particles in pine seed oil-supplemented rats. Finally, P. pinaster seed oil treatment was associated with a small decrease of liver apoC-III (P<0.02) but not in apoE, apoA-I, or apoA-II mRNA levels. The levels of circulating apo were not affected by pine seed oil supplementation. In conclusion, P. pinaster seed oil has a triglyceride-lowering effect in rats, an effect that is due to a reduction in circulating VLDL.     

Influence of dietary arachidonic acid on metabolism in vivo of 8 cis, 11 cis, 14-eicosatrienoic acid in humans

This study investigated the influence of dietary arachidonic acid (20∶4n-6) on Δ5 desaturation and incorporation of deuterium-labeled 8cis, 11cis, 14-eicosatrienoic acid (20∶3n-6) into human plasma lipids. Adult male subjects (n=4) were fed diets containing either 1.7 g/d (H120∶4 diet) or 0.21 g/d (LO20∶4 diet) of arachidonic acid for 50 d and then dosed with a mixture containing ethyl esters of 20∶3n-6[d4] and 18∶1n-9[d2]. A series of blood samples was sequentially drawn over a 72-h period, and methyl esters of plasma total lipid, triacylglycerol, phospholipids, and cholesteryl ester were analyzed by gas chromatography-mass spectrometry. Based on the concentration of 20∶3n-6[d4] in total plasma lipid, the estimated conversion of 20∶3n-6[d4] to 20∶4n-6[d4] was 17.7.±0.79% (HI20∶4 diet) and 2.13±1.44% (LO20∶4 diet). The concentrations of 20∶4n-6[d4] in total plasma lipids from subjects fed the HI20∶4 and LO20∶4 diets were 2.10±0.6 and 0.29±0.2 μmole/mL plasma/mmole of 20∶3n-6[d4] fed/kg of body weight. These data indicate that conversion of 20∶3n-6[d4] to 20∶4n-6[d4] was stimulated 7-8-fold by the HI20∶4 diet. Phospholipid acyltransferase was 2.5-fold more selective for 20∶3n-6[d4] than 18∶1n-9[d2], and lecithin:cholesterol acyltransferase was 2-fold more selective for 18∶1n-9[d2] than 20∶3n-6[d4]. These differences in selectivity were not significantly influenced by diet. Absorption of ethyl 20∶3n-6[d4] was about 33% less than ethyl 18∶1n-9[d2]. The sum of the n-6 retroconversion products from 20∶3n-6[d4] in total plasma lipids was about 2% of the total deuterated fatty acids. Neither absorption nor retroconversion appears to be influenced by diet.     

Arachidonic, 5, 11, 14, 17-eicosatetraenoic and related acids in plants—Identification of unsaturated fatty acids

Arachidonic and related fatty acids which normally are found only in animals or microorganisms have been isolated and identified from several mosses and ferns. Fatty acids with a double bond in position 5, separated by more than one methylene group from other double bonds, have been found inGinkgo biloba andEquisetum. Analyses of fatty acids from numberous plants, in particular their chlorophyll containing parts, are listed according to components. The experimental part gives details on structure determination of the usual methylene-interrupted fatty acids by ozonization-hydrogenation-GLC. Alkaline isomerization combined with these procedures was applied to determine the unusual double bond structures. The method permits positional identification of an internal double bond.     

The metabolism of 1-14C-palmitic acid in the testis of the rat

The metabolism of 1-¹⁴C-palmitic acid was studied in rat testis at various intervals after intratesticular injection and after a 2 hr incubation period. Significant catabolism occurred as evidenced by production of¹⁴CO₂ in both in vivo and in vitro experiments. Of the¹⁴C activity retained in the injected testis, less than 15% remained as free fatty acid after 2 hr and less than 5% by the end of 2 weeks. Activity of¹⁴C appeared in phosphatides faster than in the triglyceride fraction, and with time (1–2 weeks) the activity in phosphatides decreased relative to that in triglycerides. In phosphatides of these experiments ca. 80% of the¹⁴C was in the palmitic acid fraction and the balance predominantly (98%) in palmitate with the balance in stearate and oleate. By the first and second weeks almost half of the¹⁴C-palmitate present in the testes had been newly synthesized from¹⁴C-acetyl CoA resulting from oxidation of the administered 1-¹⁴C-palmitate. In the incubated samples the only fatty acid with¹⁴C activity in any lipid fraction was palmitate. In these experiments ca 90% of the¹⁴C was in the free fatty acid fraction, 7% in the phosphatides and 2% in the triglycerides.     

Influence of dietary fat on metabolism of (14-14C)erucic acid in the perfused rat liver. Distribution of metabolites in lipid classes

Two groups of rats were fed diets containing 20% by weight of either partially hydrogenated marine oil supplemented with sunflower seed oil (PHMO) or palm oil (PO) for 8 wk. Using a liver perfusion system, the effect of dietary long chain monoenoic fatty acids on the uptake and metabolism of [14-¹⁴C]erucic acid was studied. The perfusion times were 15 and 60 min, respectively. The two groups showed equal ability for erucic acid uptake in the liver but differed in the channeling of the fatty acids into various metabolic pathways. A higher metabolic turnover of 22∶1 in the PHMO livers relative to the PO livers was demonstrated by an increased recovery of total [¹⁴C]labeling in the triglyceride (TG) and phospholipid (PL) fractions, already evident after 15 min of perfusion. The chainshortening capacity was highest in the PHMO group, reflected by a higher [¹⁴C]18∶1 incorporation in both TG and PL, and increasing from 15 to 60 min of perfusion. The amount of [¹⁴C]18∶1 found in PL and TG after 60 min of perfusion of livers from rats fed PO corresponded to that shown for the PHMO group after 15 min. The PL demonstrated a discrimination against 22∶1 compared to TG, and, when available, 18∶1 was highly preferred for PL-synthesis. The total fatty acid distribution in the TG, as determined by gas liquid chromatography (GLC), reflected the composition of the dietary fats. In the total liver PL, 22∶1 and 20∶1 were present in negligible amounts, although the PHMO diet contained 12–13% of both 22∶1 and 20∶1. In the free fatty acid fraction (FFA), the major part of the radioactivity (≈80%) was [14-¹⁴C]erucic acid, and only small amounts of [¹⁴C]18∶1(<2%) were presents, even after 60 min of perfusion. The shortened-chain 18∶1 was readily removed from the FFA pool and preferentially used for lipid esterification.     

Taxus baccata seed oil: A new source ofcis-5,cis-9-octadecadienoic acid

Methyl esters prepared from the seed oil of the coniferTaxus baccata L. were found by gas liquid chromatography to contain 12% of a component which, when isolated by preparative thin layer chromatography and characterized by mass spectrometry, ozonolysis and nuclear magnetic resonance, was identified ascis-5,cis-9-octadecadienoic acid.     

Synthesis of the conjugated trienes 5E,7E,9E,14Z,17Z-eicosapentaenoic acid and 5Z,7E,9E,14Z,17Z-eicosapentaenoic acid, and their induction of apoptosis in DLD-1 colorectal adenocarcinoma cells

During the course of our recent study on the antitumor effect of conjugated eicosapentaenoic acids (CEPA), we found that acid mixtures prepared by treating EPA with KOH in ethylene glycol induced potent apoptotic cell death in human tumor cells via membrane phospholipid peroxidation. Interestingly, the KOH-treated CEPA mixtures were more cytotoxic than EPA and CLA and had no effect on normal human fibroblast cells. To identify the specific cytotoxic FA in the CEPA mixture, we synthesized possible candidates for the active species. Here, we report the synthesis of (5E,7E,9E,14Z,17Z)-5,7,9,14,17-eicosapentaenoic acid (E-CEPA) and its 5-(Z) isomer (Z-CEPA), both of which are conjugated trienes that exist naturally in red algae (Ptilota filicina J. Agardh). E-CEPA and Z-CEPA were synthesized from methyl 5-oxopentanoate in six steps, using three types of Wittig reactions as the key steps. Next, we examined the cytotoxicity of E-CEPA and Z-CEPA in human tumor cells and confirmed their bioactivity. Both E-CEPA and Z-CEPA had a strong cytotoxic reaction in tumor cells, and this effect occurred through induction of apoptosis.     

cis-9,trans-11 and trans-10,cis-12 CLA affect lipid metabolism differently in primary white and brown adipocytes of Djungarian hamsters

We explored whether CLA isomers and other C₁₈ FA affect (i) lipid content and FA concentrations in total adipocyte lipids, (ii) FA synthesis from glucose in TAG and phospholipids of primary brown (BAT) and white adipocytes (WAT), and (iii) mRNA expression of uncoupling protein 1 (UCP1) in primary brown adipocytes of Djungarian hamsters (Phodopus sungorus). c9,t11-CLA, oleic, linoleic, and α-linolenic acid increased whereas t10,c12-CLA decreased lipid accumulation in both adipocyte types. t10,c12-CLA treatment affected FA composition mainly in BAT cells. CLA incorporation into lipids, in particular c9,t11-CLA, was higher in BAT. In both cell types, t10,c12-CLA treatment reduced the incorporation of glucose ¹³C carbon into FA of TAG and phospholipids, whereas c9,t11-CLA, linoleic, and α-linolenic acid either did not influence or dose-dependently increased glucose carbon incorporation into FA. UCP1 mRNA expression was inhibited by t10,c12-CLA but increased by c9,t11-CLA, linoleic, and α-linolenic acid. It is concluded that c9,t11-CLA and t10,c12-CLA have distinctly different effects on lipid metabolism in primary adipocytes. The effects of c9,t11-CLA are similar to those of other unsaturated C₁₈ FA. The opposite effects of c9,t11-CLA and t10,c12-CLA are evident in both WAT and BAT cultures; however, brown adipocytes seem to be more susceptible to CLA treatment.     

Dietary effect of gamma-linolenic acid on the lipid profile of rat fed erucic acid rich oil

This study evaluated the effects of dietary supplementation of gamma-Linolenic acid (18:3n-6, GLA) on the lipid profile of serum and other tissues of rats fed erucic acid (C22:1) rich oil like mustard oil. The rats were fed diet containing 20% mustard oil as erucic acid rich oil and 20% groundnut oil as dietary fat. These groups were kept as reference groups. Another group fed diet containing 20% fat to which evening primrose oil as a source of GLA was blended with mustard oil and groundnut oil at 5% level. The feeding experiment was done for 4 weeks. In another set mustard oil fed group was kept as control while the experimental group was fed evening primrose oil as a source of GLA blended with mustard oil at 2.5% level. The feeding experiment was carried out for 12 weeks. The other dietary components remained same for all the groups. After the scheduled feeding period, it was found that there was no significant change in weight gain, food intake and food efficiency ratio. It was found that dietary GLA resulted in significant decrease in serum triglyceride (TG) and very low density lipoprotein (VLDL) cholesterol and significant increase in high density lipoprotein (HDL) cholesterol in serum in the experimental group. In liver total cholesterol (TC) is significantly higher and in heart and liver TG is significantly lower in GLA fed group.     

Lipids in chinese medicine. Characterization of allcis 5,11,14,17-eicosatetraenoic acid inBiota orientalis seed oil and a study of oxo/furanoid esters derived fromBiota oil

The fatty acid composition ofBiota orientalis seed oil consists of palmitic (5.1%), stearic (3.4%), oleic (15.3%), linoleic (25.6%), linolenic (34.7%), C20:3(11c,14c,17c) 4.9%, and C20:4(5c,11c,14c,17c) 10.5%. The unsaturated fatty esters derived fromBiota oil were epoxidized and subsequently treated with NaI-PrI-DMSO. Chromatographic separation of the complex product mixture revealed the presence of C18-oxo, C18-furanoid, and C18-and C20-oxo-furanoid esters. Epoxidation of a pure sample of C20:4(5c,11c,14c,17c) followed by NaI-PrI-DMSO treatment gave a mixture of C20-dioxo-furanoid esters. The positions of the oxo and furanoid groups in the various derivatives were determined by GC/MS analysis.     

Effect of a diet rich in sunflower oil on aspects of lipid metabolism in the genetically-obese rat

Aspects of the lipid metabolism of male, obese and lean Zucker rats were compared using animals which had been fed ad libitum for 32 days on a diet (HS) which contained 200 g sunflowerseed oil/kg or one (LS) which contained 50 g/kg of the oil. When compared with the LS diet, the HS diet decreased the characteristic lipid accretion in the liver of obese rats from 126 mg (LS) to 81 mg (HS)/g wet weight; corresponding values for the lean rats were 39 mg and 56 mg/g wet weight of liver, respectively. The HS diet depressed lipid synthesis de novo by liver homogenates and decreased the Δ9-desaturase activity of liver microsomes from obese and clean rats by about 50%. Δ9-Desaturase activity in vitro was also depressed by the addition of linoleic acid to liver microsomes from both obese and lean rats fed ad libitum on a standard laboratory diet. Depressed Δ9-desaturase activity, due to ingestion of the HS diet, was reflected in lower ratios of 16∶1/16∶0 and 18∶1/18∶0 fatty acids in tissue lipids from obese and lean rats. Ingestion of the HS compared with the LS diet resulted in increased proportions of 18∶2ω6 in liver lipids and adipose tissue triacylglycerols of obese and lean rats. The HS diet also increased the proportions of 20∶4ω6 in adipose triacylglycerols of obese and lean rats and in liver lipids of obese animals but not in their lean littermates.     

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

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.     

Effects of rapeseed oil on fatty acid oxidation and lipid levels in rat heart and liver

The comparative rates of oxidation of erucic and oleic acids and of their CoA esters were studied in heart and liver mitochondria of rats fed a standard diet or semisynthetic diets containing 25% of the calories as either rapeseed oil (46.6% erucic and 10.4% eicosenoic acid) or olive oil, for a period of 5 months. The long exposure to the diet containing 25% rapeseed oil did not alter the oxidative activity of mitochondria and did not induce morphological changes in the heart. It is confirmed that erucic acid is oxidized in mitochondria at lower rates than other long chain fatty acids and that its activation as CoA derivative may be one of the rate limiting steps of the overall oxidation process. Total lipids and triglycerides do not significantly change in the heart whereas they increase in the liver of rats fed the diet containing rapeseed oil.     

Dietary lipid,fatty acid synthesis and cholesterol metabolism in aging rats

Male and female rats were fed diets containing 2% of calories as corn oil or that plus 40% of calories as beef tallow or corn oil. After 3, 6, 12 and 18 months groups were given 4-¹⁴C-cholesterol ip, and feces were collected for 9 days. Just prior to necropsy³H-acetate was administered ip. Samples of serum, liver, heart and carcass were obtained for analysis. Concentrations of fatty acids and cholesterol, synthesis of those and recovery of ring-labeled steroid are reported. Mortality from acute respiratory disease was very high in male rats fed beef tallow or low fat diets and very low in those fed the corn oil diet. In females, only beef tallow diet resulted in a high mortality rate, and this was lower and at a later age than in males. The most notable effects of age were in relation to fatty acid synthesis and presence of¹⁴C-acidic steroid in the carcass. In 3-month-old rats both fats depressed fatty acid synthesis in comparison to the low fat diet. At later ages beef fat ceased to depress fatty acid synthesis in both sexes. Corn oil continued to depress fatty acid synthesis up to 12 months in males and 18 months in females. The presence of¹⁴C-acidic steroid in carcass was substantial in 6-month-old rats and constituted ca. 40% of recovered¹⁴C in 18-month-old rats. The possibility that the increase in acetate incorporation into fatty acids with age in fat feeding is related to chain elongation rather than de novo synthesis is discussed. Both the presence and amount of acidic steroid in the carcass are notable and may be of importance in constructing models of cholesterol turnover. Presented in part at the AOCS Sterol Symposium, April 1970, and the Federation of American Societies for Experimental Biology, April 1971. Scientific Series Paper No. 1536, Colorado Agricultural Experiment Station.     

The structure of the triacylglycerols,containing punicic acid,in the seed oil ofTrichosanthes kirilowii

Triacylglycerols of the seed oil ofTrichosanthes kirilowii have been resolved by high-performance liquid chromatography (HPLC) in the silver-ion and reverse-phase modes. The fatty acids were identified by gas chromatography/mass spectrometry as the picolinyl esters. The main components arecis,cis-C18:2n-6 (38.2 mole%), C18:3_9c,11t,13c (punicic acid, 38.0 mole%), andcis-C18:1n-9 (11.8 mole%). Small amounts of C18:3_9c,11t,13t (α-eleostearic acid) and C18:3_9t,11t,13c (catalpic acid) were detected. Silver-ion HPLC exhibited excellent resolution in which fractions were resolved on the basis of the number and configuration of double-bonds. In this instance, the strength of interaction of a conjugated trienoic double-bond system with silver ions seemed to be between that of dienoic and monoenoic double bond systems. The triacylglycerols were also separated into 20 fractions by reverse-phase HPLC, and the fractionation was achieved according to the partition number in which a conjugated trienoic double bond was not equivalent to three monoenoic double bonds in a molecule with a given chainlength. The principal triacylglycerol species are (C18:2n-6) (C18:3_9c,11t,13c )₂ (28.3 mol% of total), (C18:1n-9)(C18:2n-6) (C18: 3_9c,11t,13c ) (19.0 mol%), and (C18:2n-6)₂(C18:3_9c,11t,13c ) (16.2 mol%), while simple triacylglycerols such as (C18:3_9c11t,13c )₃ and (C18:2n-6)₃ were present as minor components only (<1.0 mol%). Species esterified with conjugated trienoic acids comprise more than 96% of the total. Stereospecific analysis gave rise to insurmountable difficulties, but it is evident that there is some asymmetry in the distribution of fatty acids in the molecules.     

2-Aminoethylphosphonic acid metabolism in the rat

Time course studies of the incorporation of radioactive 2-aminoethylphosphonic acid (AEP) into the tissues of rats demonstrated that maximum incorporation into the liver lipids occurred within 12 to 30 hr after injection, compared to 2 to 3 hr for the incorporation of phosphorylethanolamine. Little incorporation of AEP was observed in the other tissues investigated (heart, lung, spleen, adipose, kidney). The AEP was incorporated to the greatest extent into 1,2-diacylglyceryl-aminoethylphosphonate (diacylglyceryl-AEP), the phosphonate analogue of phosphatidylethanolamine, with some incorporation into the lyso derivative. Diacylglycerol-AEP apparently was not further metabolized by the rat; no methylation of diacylglyceryl-AEP to phosphonolecithin was observed. Subcellular fractionation was performed on the livers of rats who received³H-AEP 12, 30, 36, and 48 hr prior to sacrifice. The greatest amount of radioactivity was recovered in the soluble fractions. Lipid extraction was performed on the subcellular fractions, and most of the radioactivity present in the lipids was found in the microsomal fraction, with the next highest recovery in the mitochondrial and nuclear fractions. This work is based upon a thesis submitted by J.C.-J. to the Graduate College of the University of Illinois at the Medical Center in partial fulfillment of the requirements for the Ph.D. degree in Biological Chemistry. Present Address: Department of Biochemistry, Northwestern University Medical Center, Chicago, Illinois, 60611.