Serum Lipid Composition Research Articles

Effects of Isoprothiolane and Phytosterol on Adipocyte Metabolism and Fatty Acid Composition of Serum and Tissue Lipids in Rats.

Isoprothiolane at a dose of 250 mg/kg or phytosterol 50 mg/kg was orally administered to rats once a day for 2 weeks. Basal [U-14C]glucose conversion rate to total lipids in isolated adipocytes of the rats was significantly decreased by treatment with isoprothiolane (54%) or phytosterol (82%). Adipocytes from the rats with isoprothiolane released less glycerol than those from control rats only at an epinephrine concentration of 10 microM. The serum level of total cholesterol was depressed by phytosterol ingestion. The level of non-esterified fatty acids (NEFA) was increased by isoprothiolane. Desaturation in fatty acid composition of phospholipid or cholesterol ester was observed in serum, liver and adipose tissue of the rats treated with either drug. These results suggest that either drug may have common effects by preventing lipid deposition into adipocytes and accelerating fatty acid desaturation in tissue lipids.

乳用雄子牛と雌子牛の発育段階における血清のビタミンA, ビタミンE, セレニウム, 脂質分画および血液グルタチオンペルオキシダーゼ活性の変化

Ninety bull calves for fattening and thirty heifer calves of the Holstein breed were classified into five growth stages (stage I: 7 days old; stage II: 1 month old; stage III: 3 months old; stage IV: 6 months old; stage V: 12 months old; stage VI: 17 to 18 months old) and blood chemical components including serum lipid fractions, vitamin A, vitamin E (tocopherol), selenium and blood glutathioneperoxidase activity were examined during each of these growth stages.During the fattening stage (stage V to VI) of bull calves, serum lipid fractions including total lipid, phospholipid, total cholesterol, ester cholesterol and lipid peroxide, and serum tocopherol levels increased significantly compared with the levels of heifer calves in the same growth stages, but the levels of serum retinol and erythrocyte tocopherol decreased to the contrary. There were many correlations between the level of serum tocopherol and the serum lipid compositions including phospholipid, total cholesterol and total lipid. The increase in the serum lipid levels during the fattening stage of bull calves seemed to reflect the development of the fatty tissue. Also, the decrease in erythrocyte tocopherol which is an indication of bioavailable tocopherol might be caused by the increase in the shift to fatty tissue of tocopherol.The serum selenium level and blood glutathioneperoxidase activity decreased markedly from stage V to VI for the heifer calves, and it was suggested that the decrease in both blood components was due to the low selenium diet.

Valeur des lipides sanguins comme marqueurs d'atteinte vasculaire chez le diabétique

In a group of 600 diabetics, coronary heart disease, and peripheral vascular disease were related to serum lipid composition. The best discriminative variables were total cholesterol to HDL cholesterol ratio, apoproteines B and A1 and triglycerides.

Characteristics of fatty acid composition of adipose tissue and serum lipids in reindeer calves

Abstract: Fatty acid composition of adipose tissue and serum lipids were studied in newborn and growing (1.5-month-old) reindeer. Material was collected during 1985 and 1986 at the Kaamanen research station. Lipids were extracted with methanolchloroform and fatty acid methyl esters of lipid fractions were analysed by gas liquid chromatograph. Fatty acids of adipose tissue triglycerides in newborn calves were predominantly unsaturated (51%) referring to fluid properties of brown adipose tissue lipids. The dominant fatty acid was oleic acid (18:1) with 46% followed by palmitic acid (16:0) with 30% and stearic acid (18:0) with 15%. Triglycerides (TG) contained 3% polyunsaturated fatty acids (PUFA), the majority of which was essential fatty acids (EFA). In growing reindeer adipose tissue T G were predominantly saturated (67%). The dominant fatty acid was 16:0 (34%) followed by 18:1 (29%) and 18:0 (25%). Adipose tissue phospholipids (PL) were mainly unsaturated in both age groups. The proportion of P U F A was 23%, of which majority was EFA, necessary to normal structure and function of biomembranes. A high correlation existed between fatty acid composition of adipose tissue T G and P L with serum T G in newborn calves (r = 0.982 and 0.924). Fatty acids of serum T G were saturated by 54%. The dominant fatty acids were 18:1, 16:0 and 18:0 with percentages of 38,32 and 12, respectively.

Effects of two prototypic polychlorinated biphenyls (PCBs) on lipid composition of rat liver and serum

Mature male Sprague-Dawley rats received a single IP injection of either 2,2′,4,4′,5,5′-hexachlorobiphenyl (HCB), 3,3′,4,4′-tetrachlorobiphenyl (TCB) (300 μm/kg) in corn oil (10 ml/kg) or the corn oil vehicle alone, and were killed four days later after having been fasted overnight. The vehicle control group consisted of rats which were allowed free access to feed as well as pair-fed animals. Lipid analyses were conducted on liver, hepatic microsomes and serum. TCB- (but no HCB-) treatment resulted in a statistically significant increase in total liver lipids and triglycerides. Liver phospholipids remained unchanged. Both PCBs increased the cholestrol and phospholipids content of the liver microsomal fraction. Serum lipids measured were not statistically different from control values. While HCB had little effect on the fatty acid composition of liver lipids, TCB caused an increase in C 18:1 (n-9) and a decrease in C 20:4 (n-6). Both PCBs increased C 18:0 in the hepatic microsomal fraction, but TCB also decreased C 16:0. Neither PCB altered the fatty acid composition of serum total lipids. These data are consistent with the concept that specific alterations in lipid metabolism are dependent on the structure of the PCB.

Changes in fatty acid composition of rat liver and serum induced by distal small bowel resection

The serum lipid composition and the fatty-acid profiles of the major lipid fraction (triglycerides, esterified cholesterol, and phospholipid) of liver and serum were examined 6 weeks after both 50% and 75% distal small bowel resection (DSBR). Total serum lipid content did not modify after DSBR. Esterified cholesterol and phospholipid levels of the serum did not significantly change after the operation. However, a significant increase in both free cholesterol and triglyceride levels was observed after DSBR. Different fatty acid changes in the liver and serum lipid fractions were found after DSBR, with the greatest differences in the hepatic esterified cholesterol fraction. These results suggest that DSBR affects both the lipid composition and the fatty acid composition of major lipid fraction of liver and serum.

The effect of retinol on the changes of lipid composition in serum of rabbit.

Serum retinol is considered to increase when the beef cattle is fattened up or in a muscle marbling process. We examined the effects of retinol on the total lipids, triglycerides, phospholipids, cholesterols and lipid peroxides using rabbits. The animals were given 15,000 or 150,000 IU/kg of retinol (retinyl palmitate) intramuscularly once every 4 days for 48 days. When treated with 150,000 IU/kg of retinol, animals showed changes in the serum concentrations of total lipids, triglycerides, phospholipids, cholesterols and lipid peroxides. In particular, lipid peroxides remarkably increased. These results indicated that retinol accelerated the oxidation of serum lipids and that the effect of retinol was more prominent in unsaturated fatty acids than in saturated fatty acids. Furthermore, it was suggested that a large amount of administrated retinol may cause qualitative change of lipid composition in muscle.

Biliary lipid composition in monozygotic and dizygotic pairs of twins.

The relative contribution of genetic factors to biliary and serum lipid composition was studied in 17 monozygotic and 18 dizygotic middle aged male pairs of twins. Cholesterol precursors, squalene and Methylated sterols which reflect the activity of cholesterol synthesis were also measured. Pairwise intraclass correlations were determined for monozygotic and dizygotic twin pairs and heritability estimates were calculated. Molar % of biliary cholesterol and percentage distribution of biliary cholic acid and particularly deoxycholic acid showed significant pairwise correlations within the monozygotic but not the dizygotic pairs. Similar correlations were found for total biliary methylsterols and of the methylsterol subfractions for the two methostenols but not for squalene, lanosterol and dimethylsterols. In serum, the precursor sterols, but not squalene, showed even higher pairwise correlations in the monozygotic twins than the corresponding precursors in bile. Molar per cent of bile acids and phospholipids and cholesterol saturation index were not correlated significantly in either twin pairs, but the pairwise correlations tended to be higher in the monozygotic than in the dizygotic pairs. Gall stones were found in seven monozygotic and three dizygotic subjects. Two monozygotic twin pairs were concordant for gall stones; all the dizygotic pairs were discordant. Overall, these data suggest that molar percentage of biliary cholesterol, bile acid composition, cholesterol synthesis, bile cholesterol saturation, and gall stone formation may be under a significant genetic control.

Detergent induced changes in serum lipid composition in rats

The influence of in vivo administration of detergents on serum lipid composition was studied in rats. Male Wistar rats received 50 mg Emulgen 913 (polyoxyethylene nonylphenylether, a nonionic detergent) or SDS (sodium dodecylsulfate, an anionic detergent) per kg of body weight intraperitoneally for 3 consecutive days. Emulgen 913 and SDS administration increased the level of cholesterol esters and phospholipids, respectively. But Emulgen 913 administration reduced the level of triglycerides in the serum, and SDS administration reduced also the levels of triglycerides and cholesterol esters. In spite of the changes in serum lipid composition, the administration of these detergents did not affect the amount of total lipids in rat serum. The proportion of palmitic, oleic, and docosahexaenoic acids in phospholipids was decreased by the administration of Emulgen 913 while the level of arachidonic acid was raised. However, the level SDS administration had no effect on the fatty acid composition of the serum phospholipids. On the other hand, both Emulgen 913 and SDS administration showed an effect on the fatty acid composition of triglycerides. It is postulated that liver damage due to administration of detergents is responsible for the changes in serum lipid and fatty acid composition in detergent-treated rats.

Fatty acid composition of serum lipids in patients with a coronary bypass operation.

The fatty acid composition of serum phospholipids and cholesteryl esters was analysed in 71 male patients with angiographically defined three-vessel coronary artery disease (CAD) selected for a coronary bypass operation. Their 71 control subjects were matched according to age, sex, smoking, relative weight, and absence of CAD. The concentrations of fatty acids, 14:0, 16:0 and 16:1 of the serum phospholipids, were significantly (P less than 0.01, P less than 0.05 and P less than 0.01, respectively) higher in CAD patients than in the controls. On the other hand, linoleic (18:2 omega 6), linolenic (18:3 omega 3) and arachidonic (20:4 omega 6) acids were at a significantly lower level in the patients when compared to the controls. The polyunsaturated/saturated fatty acids (P/S) ratio in serum phospholipids was significantly (P less than 0.01) lower in the patients than in the controls. In the cholesteryl ester fraction the results paralleled those of the phospholipids. Significant correlations were obtained between the polyunsaturated fatty acids and the high density lipoprotein cholesterol or apolipoprotein A-I in the control subjects but most of these correlations were absent in the patients. Our present results further support the importance of linoleic acid in the protection against atherosclerosis. However, no unequivocal evidence on the possible beneficial effect of long-chain omega 3-fatty acids in comparison with omega 6-acids was obtained.

Dietary saturated fat level alters the competition between α‐linolenic and linoleic acid

Male weanling rats were fed semi-synthetic diets high in saturated fat (beef tallow) vs high in linoleic acid (safflower oil) with or without high levels of alpha-linolenic acid (linseed oil) for a period of 28 days. The effect of feeding these diets on cholesterol content and fatty acid composition of serum and liver lipids was examined. Feeding linseed oil with beef tallow or safflower oil had no significant effect on serum levels of cholesterol. Serum cholesterol concentration was higher in animals fed the safflower oil diet than in animals fed the beef tallow diet without linseed oil. Feeding linseed oil lowered the cholesterol content in liver tissue for all dietary treatments tested. Consumption of linseed oil reduced the arachidonic acid content with concomitant increase in linoleic acid in serum and liver lipid fractions only when fed in combination with beef tallow, but not when fed with safflower oil. Similarly, omega 3 fatty acids (18:3 omega 3, 20:5 omega 3, 22:5 omega 3, 22:6 omega 3) replaced omega 6 fatty acids (20:4 omega 6, 22:4 omega 6, 22:5 omega 6) in serum and liver lipid fractions to a greater extent when linseed oil was fed with beef tallow than with safflower oil. The results suggest that the dietary ratio of linoleic acid to saturated fatty acids or of 18:3 omega 3 to 18:2 omega 6 may be important to determine the cholesterol and arachidonic acid lowering effect of dietary alpha-linolenic acid.

Effect of taurine administration on serum lipid and biliary lipid composition in man.

The effect of oral administration of taurine (3.2 g/day, 2 weeks) on the metabolism of lipids and bile acids was studied with healthy humans. Four male subjects were fed taurine. Another five male subjects were administered 1 g of cholesterol daily for two weeks and, at intervals of two weeks, cholesterol and taurine simultaneously. Serum lipoprotein and duodenal bile were analyzed. Oral administration of taurine resulted in the increase of taurine-conjugated bile acids. However, neither serum lipid nor biliary lipid composition was altered. Addition of taurine with cholesterol administration showed elevation of both the serum low density lipoprotein cholesterol level and the lithogenic index in bile. The ratio of glycine-to taurine-conjugated bile acids was changed from 4.1 to 0.63. The ratio of cholic acid/chenodeoxycholic acid was augmented from 0.57 to 0.81. The percentage of taurocholic acid, taurochenodexycholic acid and taurodeoxycholic acid were increased about 4-fold, 2.5-fold and 3-fold, respectively. Our results suggested that taurine administration alone did not influence the serum lipid level although taurine-conjugated bile acids were increased. The taurine intake would increase serum low density lipoprotein cholesterol and biliary cholesterol levels when excessive cholesterol is administered simultaneously.

Serum lipids in the sex-linked dwarf chicken.

The concentration and fatty acid composition of serum lipids from thesex-linked dwarf chickens were compared with those from the nondwarf chickensbetween 7 and 28 weeks of age. Concentrations of free fatty acids, triglycerides, phospholipids and free or total cholesterol were higher in the dwarfs than in thenondwarfs. This trend was more evident in mature birds. Differences in fattyacid composition between genotypes or sexes were not great in growing birds.

Fish oil reduces cholesterol and arachidonic acid content more efficiently in rats fed diets containing low linoleic acid to saturated fatty acid ratios

Rats were fed diets containing a high level of saturated fatty acids (hydrogenated beef tallow) versus a high level of linoleic acid (safflower oil) at both low and high levels of fish oil containing 7.5% (w/w) eicosapentaenoic and 2.5% (w/w) docosahexaenoic acids for a period of 28 days. The effect of feeding these diets on the cholesterol content and fatty acid composition of serum and liver lipids was examined. Feeding diets high in fish oil with safflower oil decreased the cholesterol content of rat serum, whereas feeding fish oil had no significant effect on the cholesterol content of serum when fed in combination with saturated fatty acids. The serum cholesterol level was higher in animals fed safflower oil compared to animals fed saturated fat without fish oil. Consumption of fish oil lowered the cholesterol content of liver tissue regardless of the dietary fat fed. Feeding diets containing fish oil reduced the arachidonic acid content of rat serum and liver lipid fractions, the decrease being more pronounced when fish oil was fed in combination with hydrogenated beef tallow than with safflower oil. These results suggest that dietary n − 3 fatty acids of fish oil interact with dietary linoleic acid and saturated fatty acids differently to modulate enzymes of cholesterol and fatty acid metabolism.

Fatty acid composition of serum lipids and its relation to diet in an elderly institutionalized population

This study was conducted to determine the nutritional status with respect to fatty acids of 53 institutionalized elderly subjects (group A). Seven-day food records and biochemical determinations were used. The same protocol was applied to 25 healthy young adults (group B). The 1981 French Recommended Dietary Allowances were used to assess adequacy of intake. Total fat intake was found to be too high in both groups. Higher intakes of animal fats and saturated fatty acids and lower intakes of polyunsaturated fatty acids and linoleic acid were documented in group A than in group B. Elderly subjects exhibited decreased 18:2 omega 6 and 20:4 omega 6 in serum phospholipids and triglycerides. Other indicators of essential fatty acid status in group A differed from group B in the direction of deficiency (double-bond index [DBI], 0.93 +/- 0.01 vs 1.13 +/- 0.04, p less than 0.001; total omega 6, 25.07 +/- 0.46% vs 32.49 +/- 0.89%, p less than 0.001). These findings indicate that institutionalized elderly people are deficient in circulating essential fatty acids, which appears to be caused by both diet and metabolism.

Effects of age and diet on the lipid content and composition of gallbladder bile, liver and serum in laying strains of hen.

1. Changes in lipid content and composition of liver and bile during pre- and post-laying periods were investigated in hens of a laying strain. 2. The large increase in liver lipid concentration, particularly triacylglycerols, at the onset of laying was accompanied by the appearance of triacylglycerols in the bile. 3. Accumulation of triacylglycerol in the liver was increased by a diet containing maize and soyabean meal. This was associated with increases in the triacylglycerol concentration in both serum and bile. 4. Liver microsomal phosphatidate phosphohydrolase activity was positively correlated with liver triacylglycerol content in birds given the maize/soyabean meal diet. 5. The time course of triacylglycerol accumulation in the liver and associated changes in the bile triacylglycerol concentration in laying strain hens were different to those previously observed in broiler hens. 6. Over the lifetime of the bird, secretion of triacylglycerols into bile may play an important role in the prevention of fatty liver syndromes.

Rapid changes in serum, plasma and erythrocyte lipid compositions, and serum transaminase levels during continuous enteral hyperalimentation by carbohydrates alone

Twelve normal men received twice their estimated basal energy requirement by a carbohydrate solution via a nasogastric catheter during 48 hours, followed by a seven-hour fast. Subsequently, in nine of them 0.5 mg epinephrine was given subcutaneously under ongoing fasting. During hyperalimentation, serum triglycerides, phospholipids, total and free cholesterol, phospholipids/free cholesterol ratio, and plasma free fatty acids decreased, whereas the percentage of free cholesterol increased. During fasting and subsequent epinephrine administration triglycerides and free fatty acids rose without reaching basal levels. Plasma and red blood cell (RBC) fatty acid composition already changed from two hours after the start of the feeding. Most markedly, a steady decrease in RBC 18:2c,ω6, amounting to more than 17% of the basal value at the end of the observation period was found. Neither in plasma, nor in RBC a concomitant appearance of 20:3c,ω9 was seen. In RBC, the relative amounts of the saturated fatty acids increased, whereas those of monounsaturated and polyunsaturated fatty acids decreased. RBC content of total fatty acids decreased and that of cholesterol increased. The ratios 16:1 c,ω7 16:0 and 18:3 c,ω6 18:2 c,ω6 in plasma, and 20:3 c,ω6 18:2 c,ω6 in plasma and RBC increased, whereas those of 18:1 c,ω7 16:1 c,ω7 and 20:3 c,ω6 18:3 c,ω6 in plasma decreased. After 48 hours feeding serum glutamic pyruvic transaminase and glutamic oxaloacetic transaminase levels were moderately increased and rose further during fasting. Thus, continuous enteral hyperalimentation by carbohydrates alone rapidly induces profound changes in serum-, plasma-, and RBC lipid compositions and serum parameters of hepatic function. The data suggest a stimulation of de novo fatty acid synthesis, an augmentation of Δ9 and Δ6 desaturase activity along with an impairment of the chain-elongation of unsaturated fatty acids, and a shift of cholesterol from plasma to the RBC membrane.

Essential fatty acid status in southern Thai preschool children.

Essential fatty acid (EFA) status was assessed in 15 Southern Thai preschool children. The mean (+/- SD) serum linoleate (18:2 n-6), arachidonate (20:4 n-6), linolenate (18:3 n-3), eicosapentaenoate (20:5 n-3), and docosahexaenoate (22:6 n-3) percentages in the preschool children were 21.7 +/- 4.0, 6.0 +/- 1.2, 0.4 +/- 0.1, 1.2 +/- 0.8, and 4.4 +/- 1.3, respectively. Since EFA composition of total serum lipids in healthy children are not available and age and sex do not largely influence these parameters, the results of the preschool children were compared with those of 10 healthy Bangkok adults. The corresponding figures of the aforementioned fatty acids in adults were 34.9 +/- 8.5, 4.6 +/- 1.5, 0.8 +/- 0.4, 0.5 +/- 0.4, and 1.6 +/- 0.8, respectively. The data indicate linoleate and linolenate depletion in the preschool children. This was due to their low fat intake and lack of consumption of vegetable oil rich in linoleic and linolenic acids. Their high serum arachidonate percentage was probably due to the increased conversion of 18:2 n-6 to 20:4 n-6 in the presence of linolenate depletion. The significantly higher serum 20:5 n-3 and 22:6 n-3 percentages in the preschool children should be due to direct consumption of these two n-3 fatty acids from fish intake.

Dietary Fat and Mammary Cancer. II. Modulation of Serum and Tumor Lipid Composition and Tumor Prostaglandins by Different Dietary Fats: Association With Tumor Incidence Patterns<xref ref-type="fn" rid="FN1">2</xref><xref ref-type="fn" rid="FN2">3</xref>

For investigation of the role of linoleic acid (LA) and its biologically significant metabolites in mammary tumor promotion by dietary fat, a detailed study of the fatty acid group composition of serum lipids, tumor neutral lipids, tumor phospholipids, and tumor prostaglandins (PG's) was conducted in female inbred F344 rats initiated with N-nitrosomethylurea (CAS: 684-93-5) and fed diets containing various types and amounts of fat. The oils, safflower [23%, high fat (HF); 5%, low fat], corn (23%, 5%), olive (23%, 5%), and coconut (23%) varied widely with respect to their LA content and their polyunsaturate:monounsaturate:saturate ratios (9:1:1, 4.6:2.6:1, 0.6:5.9:1, and 0.008:0.05:1, respectively, for safflower, corn, olive, and coconut oils). A modified hexane-based technique was used for extraction of serum and tumor lipids. Total tumor lipids ranged from a low of 5 to a high of 228 mg/g (wet wt) with no differences found among the 7 dietary groups. The phospholipid content of the tumors ranged from 27 to 47% of total tumor lipid, again with no differences seen among dietary groups. Total serum lipids varied from a low of 3.77 mg/ml (safflower oil, 23%) to a high of 6.11 mg/ml (coconut oil, 23%), and an overall inverse trend was observed between total serum lipids and tumor incidence for the 4 HF diet groups. Serum cholesterol levels were significantly depressed in the HF safflower oil and corn oil groups compared to those in all other dietary groups and, in general, varied inversely with respect to mammary tumor incidence. Serum and tumor neutral fatty acid profiles closely reflected those of the diet, while tumor phospholipids appeared more resistant to diet-induced changes. Olive oil-fed animals exhibited high levels of oleic acid in both serum and tumor lipids. The levels of the major metabolite of LA, arachidonic acid (AA), in tumor phospholipids were highly variable and did not equate with dietary or serum LA levels. A positive association was found among dietary LA, tumor PGE2, and mammary tumor incidence among the 4 HF groups; however, no association was found between tumor AA levels and either tumor PGE2 levels or mammary tumor incidence. The results of this study suggest that dietary LA may exert its effects on mammary tumor promotion by virtue of its role as a PG precursor; but the precise steps in this sequence and possible competitive interactions between essential fatty acids, monoenes, and saturates and the PG-synthesizing system remain to be determined.

Serum fatty acid concentrations in patients on postoperative parenteral nutrition with and without fat

To examine changes in fatty acid composition of serum lipids, sixteen patients with gastric cancer were maintained on total parenteral nutrition (TPN) or intravenous feeding immediately after total gastrectomy. Subjects receiving no fat showed decreases in linoleic acid, linolenic acid and arachidonic acid and increases in palmitoleic acid and oleic acid, whereas those receiving fat emulsion showed no detectable changes. Decrease in the linoleic acid content was greater in subjects on a higher carbohydrate intake, but less in those on a higher fat intake. Multiple regression analysis of the relationships among carbohydrate intake (X1) and fat intake (X2) and changes in the linoleic acid percentage of total serum fatty acids (Y) in each case yielded an equation: Y =-4.75 X1 + 69.0 X2 - 27.9 (R = 0.885, p less than 0.05). Approximately 1 g/kg/day of fat provided in 40-50 kcal/kg/day of nonprotein energy intake was estimated to prevent decrease in the linoleic acid content in the serum fatty acid pattern during the postoperative catabolic stage.