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At least 721 records · Page 40Linked to original sources

Effects of nicotinic acid treatment on fatty acid composition of plasma lipids and adipose tissue in hyperlipidaemia.

Effects of 6-week treatment with 4 g daily of nicotinic acid on fatty acid composition in different serum lipids and in adipose tissue glycerides were studied in 31 hyperlipidemic patients. The percentages of eight fatty acids in triglycerides, phospholipids and cholesteryl esters of whole plasma as well as in subcutaneous adipose tissue glycerides were measured. Nicotinic acid treatment produced decreases in triglyceride and total cholesterol concentrations of VLDL and LDL, whereas HDL total cholesterol levels in serum increased after drug therapy, all p less than 0.01. There were reductions in the relative contents of myristic acid in plasma phospholipids (from 0.4% to 0.3%; p less than 0.05) and cholesteryl esters (from 0.9% to 0.7%; p less than 0.001). There were decreases in the percentages of stearic acid in plasma phospholipids (from 17.0% to 15.0%) and cholesteryl esters (from 1.2% to 1.0%; both p less than 0.001). The relative contents of polyunsaturated fatty acids, mainly linoleic acid, in plasma phospholipids were increased (from 32% to 33.5%; p less than 0.05). There were reductions in the linolenic acid contents of adipose tissue (from 1.5% to 1.1%) and plasma triglycerides (from 1.1% to 0.8%), both p less than 0.05, possibly indicating increased conversion of linolenic acid to prostaglandins. There was no relationship between changes in the percentages of individual fatty acids and changes in triglyceride or total cholesterol levels of whole serum and its VLDL, LDL and HDL fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

A comparison of the enzyme levels and the in vitro utilization of various substrates for lipogenesis in pair-fed lean and obese pigs.

In this study of spontaneous obesity of pigs, specific metabolic shifts were observed, which explain an increase in fat deposition. Liver tissue utilization of pyruvate and glucose for oxidation and lipogenesis showed no significant difference between lean and obese pigs. Adipose tissue utilization of glucose, acetate and glycerol for triglyceride and fatty acid synthesis was greater in obese pigs than lean pigs (P less than 0.01). No significant difference in leucine incorporation into lipid fractions was found. Of the substrates utilized, glucose supplied 86 and 94% of the glyceride-glycerol synthesized in lean and obese pigs, respectively. Glycerol was not a major contributor to glyceride-glycerol synthesis (3.5 to 5.5%), in spite of the presence of adipose tissue glycerokinase. An increase (P less than 0.05) in alanine incorporation into glucose was observed in liver tissue from obese pigs. In general, the levels of enzymes activities associated with gluconeogenesis, glycolysis, and lipogenesis supported the findings of in vitro utilization of these substrates.

Acetates↗

[A study on the lipids of Chinese liverfluke, Clonorchis sinensis]

The present study was undertaken to observe the quality and quantity of lipids in the adult worms of Chinese liverfluke, Clonorchis sinensis. Lipid extraction was done by the methods of Folch et a1. (l957) and Kenny (1952), and then the extracted lipid fractions of the worm were separated by thin layer chromatography. Those fractions were also subjected to perform the quantitative analyses of glycerides, cholesterols and phospholipids. The results obtained were summarized as follows: 1. Total amount of glyceride was 37.56 mg per gram of worm tissue and the amount of monoglyceride was 8.34 mg per gm; diglyceride, 15.46 mg per gm; and triglyceride, 12.86 mg per gm. 2. Total amount of cholesterol was 3.30 mg per gm of worm tissue, and the esterified cholesterol (1.72 mg/gm) was a little more than that of free cholesterol (1.26 mg/gm). 3. The following 8 phospholipids were detected in the worm tissue of C. sinensis, i.e., lysophosphatidylcholine, phosphatidylcholine, phophatidylinositol, sphingomyelin, phosphatidylglycerol, phosphatidylserine, phosphatidylethanolamine and an unknown phospholipid.

Journal Article↗

Effect of diet and substrate on the in vitro measurement of cholesterol and fatty-acid synthesis in hepatic tissue of Japanese quail.

A comparison of acetate, glucose, mevalonate, or water as radioactive substrates for the hepatic synthesis of cholesterol, fatty acids, and glyceride-glycerol was made in Japanese quail fed diets containing either beef fat or tuna oil. The quail fed a diet containing beef fat were fatter and had a significantly higher (P less than .01) concentration of serum cholesterol (5.6 mM per L) than that measured in the serum of quail given tuna oil (4.1 mM per L). Both in vitro cholesterol and fatty-acid synthesis were greater in the quail fed a diet of beef fat than in those fed a diet containing tuna oil. The results showed that mevalonate was the most-suitable radioactive substrate for measuring cholesterol synthesis, whereas glucose was the most-suitable radioactive substrate for measuring fatty-acid and glyceride-glycerol synthesis.

Animals↗

Effects of glycerol and glucose on the kinetics of glycerol utilization by adipose tissue in the rat.

To study the kinetics of glycerol utilization by adipose tissue in vitro as function of the concentrations of both glycerol and glucose in the incubation media, pieces of epididymal fat pad from fed rats were incubated for different times in Krebs Ringer bicarbonate supplemented with 1-14C-glycerol and purified albumin. An increase in the concentration of glycerol in the medium produces a decrease in the formation of 14CO2 and 14C-lipids from 1-14C-glycerol. When the decrease in the specific activity of the tracer is considered to calculate the respective velocities, it turns out that glycerol actually enhances the rate of synthesis of both CO2 and glyceride glycerol. Glucose enhances the rate of synthesis of CO2 and fatty acids from glycerol but decreases the rate of glyceride glycerol synthesis from the same substrate. While the Km of the glycerol effect is much lower that the physiological concentrations of glycerol the Ka and Ki of the glucose effects are above or close to its concentration in blood. The results are discussed in terms of the competitive effects of glucose and glycerol for the synthesis of alpha-glycerophosphate and the necessity of glucose for lipogenesis from glycerol in adipose tissue.

Adipose Tissue↗

[U-14C]glucose metabolism in vivo in rats rendered obese by a high fat diet.

Estimates of the glucose pool, the glucose space, the turnover rate, and the recycling of glucose were made after the injection of [U-14C]glucose into (a) obese rats fed a high fat diet and (b) rats fed a carbohydrate diet. The specific activity--time curve consisted of two components. Physiological parameters were calculated by using a two-compartment model. The glucose pool and glucose space were the same in both groups of rats. The turnover rate was 1.96 mg. min-1 for the carbohydrate-fed rats and 1.55 mg. min-1 for the fat-fed rats. There was about 12 percent recycling in both groups. In the carbohydrate-fed group, another approach based on simultaneous use of [6-14C]glucose and [6-3H]glucose yielded nearly the same values for these parameters. Respiratory excretion of CO2 and the incorporation of labeled glucose into lipids of some tissues were also measured. The rate of excretion of labeled CO2 and the conversion of labeled glucose into fatty acids in fat-fed rats were lower than in the carbohydrate-fed rats by 50 percent and 80 percent, respectively. More glucose was diverted into glyceride glycerol in the fat-fed group. It is suggested on the basis of the results that glyceride glycerol can serve as a gluconeogenic substrate in these rats where the turnover rate of glucose is much higher than the daily intake of carbohydrates.

Adipose Tissue↗

How to make things work again--troubleshooting using the GC-IDMS determination of triacylglycerols as an example.

This article describes the process of "repairing" a method which has gone out of control, using the gas-chromatographic isotope-dilution mass spectrometric (GC-IDMS) determination of total glycerides in serum, measured as glycerol. The original method used 13C2-glycerol as aqueous internal standard and 12C-tripalmitin dissolved in toluene as external standard. The modified method used tripalmitin as internal and external standard, the former being labelled uniformly on the glycerol moiety of tripalmitin (13C3-tripalmitin). In addition, glycerol-free human serum albumin was added to the external standards to "trap" the glycerol physically during evaporation of the extraction solvent after alkaline hydrolysis. The modified method was more stable than the original one and the intensity of the MS-signal in the modified method was at least 100 times stronger in the external standards than in the original method. The precision of the modified method in measuring total glycerides in serum samples (as total glycerol) was better than in the original method, the coefficients of variation being under 1.5% at concentrations between 0.8 and 3.5 mmol/l.

Carbon Radioisotopes↗

A supercritical fluid-based coating technology 1: process considerations.

A novel solvent-free particle coating process, based on the solvent properties of supercritical fluids (SCF) is described. It consists of dissolving one or more coating materials in supercritical CO(2) and then adjusting T/P conditions in the autoclave so that the coating material becomes insoluble in the CO(2). This insolubilization step causes a coating to deposit on the surface of suspended particles. This process has been applied to bovine serum albumin and sugar granules. Coating was effective, but different morphologies were obtained depending on the coating material used. A discontinuous coating has been made using trimyristin, since this material precipitates as micro-needles. Conversely, a smooth, regular coating has been obtained with a commercially available mixture of glycerides and glyceride esters of PEG (Gelucire 50/02) acting like a film-forming agent.

Capsules↗

[Pathophysiological significance of steatorrhea as well as of hydroxystearic acids in the feces of calves with diarrhea].

UNLABELLED: The objective of this study was to determine the digestibility of milk lipids in calves with diarrhoea, the pathophysiological effects of fat intake on the course of the disease and the conversion of malabsorbed longchain fatty acids to secretory effective hydroxy fatty acids by the intestinal flora. ANIMALS: 32 male calves of the breed "Deutsches Fleckvieh" with spontaneous occurring diarrhoea, age 3-14 days. Reference group: 6 clinically healthy calves of the same age group. Feed: whole milk, daily ration corresponding to 10% of the BM, divided into 3 meals; supplementary oral rehydration solution as required. METHODS: Quantitative collection of the faeces excreted over a period of at least 72 hours, determination of fatty acids and glycerides, identification and quantification of hydroxystearic acids in the faeces by gas chromatography; calculation of the apparent digestibility of the milk lipids. RESULTS: The apparent digestibility of the milk lipids was in part considerably reduced in direct relation (r = 0.8) to the severity of the diarrhoea. In the case of daily fecal outputs of over 50 g/kg BM (watery diarrhoea), the apparent fat digestibility was reduced below 50%. Even so, the apparent digestibility correlated positively with the milk intake (r = 0.5). The fat excretion in the patients showed an average of 1.4 g/kg BM/24 h and was thus nearly nine times higher in comparison to the reference group (0.16 g/kg BM/24 h). In the case of severe diarrhoea, fat excretion rates of over 2 (up to max. 5.8) g/kg BM in 24 hours were recorded. However, in the main (approx. 70%) it was not glycerides but nonesterified fatty acids. A part of the longchain fatty acids were converted to hydroxy fatty acids by the intestinal flora. It was possible to quantify alpha-, 10(9)- and 12-hydroxystearic acids individually in the faeces of both healthy calves and those with diarrhoea. However, the total concentration of hydroxystearic acids in the faces of 26 out of 32 patients was considerably under the secretory effective concentration of 2 mmol/kg (mean = 1.5 mmol/kg), the other six lay between 2.9 and 11.6 mmol/kg. Only a weakly positive correlation (r = 0.23 or 0.24) existed between the amount of milk intake and the fecal concentration resp. excretion of hydroxystearic acids. CONCLUSIONS: There was no evidence that the consumption of milk lipids influenced the diarrhoea negatively. In individual cases, it could not be completely excluded that fluid and electrolyte absorption was affected by hydroxystearic acids produced in the intestine, but the quantitative effects of this process are of minor significance in comparison to other diarrhoea inducing factors.

Animals↗

Constituents of Carapa guianensis Aubl. (Meliaceae).

Nine compounds were isolated from the EtOH extraction of the twig of Carapa guianensis Aubl. On the basis of spectroscopic methods, their structures were elucidated as 1,3-di-benzene carbon amine-2-octadecylic acid-glyceride (1), hexacosanoic acid-2,3-dihydroxy-glyceride (2), ursolic acid (3), naringenin (4), scopoletin (5), 3,4-dihydroxymethylbenzoate (6), 2,6-dihydroxymethylbenzoate (7), tetratriacontanoic acid (8), triacontanoic acid (9) respectively. Among them 1 was new, 2 was firstly isolated from nature, and 3-9 were obtained from this plant for the first time.

Chemical Phenomena↗

Relationship between testosterone and hepatic lipids in mature male bonnet monkeys, Macaca radiata (Geoffroy).

Administration of testosterone propionate (TP; 1 mg/kg body weight/day; im, for 30 days) to mature male bonnet monkeys, decreased total lipids, glyceride glycerol and cholesterol concentrations in hepatic tissue. The decrease in glyceride glycerol was due to decrease in monoacyl and triacyl glycerol. Both, free and esterified cholesterol were decreased after testosterone administration. Eventhough, total phospholipid was not significantly altered, phosphatidylserine and cardiolipin were increased, due to testosterone administration. Testosterone inhibited NADP-isocitrate dehydrogenase activity in liver. The findings suggest that testosterone acts as a lipolytic hormone and its action may be direct through its specific receptors in liver.

Animals↗

Conversion of (U-14C)-glycerol, (2-3H)-glycerol and (1-14C)-palmitate into circulating lipoproteins in the rat.

The in vivo formation of labelled very low density lipoproteins (VLDL) from (U-14C)-glycerol, (2-3H)-glycerol and (1-14C)-palmitate was studied in fed female rats. The rate of disappearance of radioactivity from plasma after the i.v. injection with these tracers was similar for (U-14C)-glycerol and (1-14C)-palmitate. With (2-3H)-glycerol, plasma radioactivity at 10 min was lower than with the other substrates although it did not change thereafter. A certain proportion of radioactivity administered as glycerol appeared in plasma lipids, mainly in the VLDL glyceride glycerol fraction, although when (U-14C)-glycerol was the substrate, a considerable portion also appeared in the esterified fatty acids of these lipoproteins. When using (1-14C)-palmitate, practically all the circulating labelled esterified fatty acids appeared in the VLDL fraction, while the labelled free fatty acids appeared in lipoprotein of higher density, presumable free fatty acid-albumin complexes. This data is discussed in terms of the role of the liver in the rapid, continuous cycling of these substrates to yield VLDL-glycerides for their extrahepatic utilization.

Animals↗

Effect of corticosterone on epididymal lipids in pubertal rat.

Serum corticosterone excess was induced by the administration of corticosterone acetate to adrenal intact rats. Different lipid classes were studied in unwashed and washed (epididymal sperm and fluid free) caput and cauda epididymides. The unwashed caput epididymidis registered a significant decrease in total lipid, cholesterol and phospholipid while total glyceride glycerol and its fractions were not altered after corticosterone treatment. Among phospholipid fractions phosphatidyl inositol, choline and ethanolamine showed a significant decrease. Unlike the unwashed caput epididymidis, the washed caput region recorded a marked increase in total lipid, glyceride glycerol and its fractions. However, total lipid in the washed cauda region significantly increased and the increase was mainly due to triacyl glycerol. Though the phospholipid fractions phosphatidyl choline and ethanolamine showed an increase, the total phospholipid was not altered significantly. Serum testosterone and prolactin registered a significant decrease while gonadotropins were unaltered. On the withdrawal of corticosterone treatment, all the lipid classes turned to normalcy along with serum testosterone and prolactin. It is concluded that corticosterone excess favours lipid accumulation in the sperm free epididymal tissue and its influence on epididymis is region specific and reversible.

Animals↗

The role of adipose tissue in glucose utilization in irradiated rats.

The authors studied the conversion of U-14C-glucose to total lipids, fatty acids and glyceride glycerol in the epididymal adipose tissue of rats X-irradiated with a single whole body dose of 14.4 Gy X-rays. Analyses were carried out 1, 24, 48 and 72 h after irradiation. In the adipose tissue of irradiated rats, the incorporation of 14C-glucose into all the lipid fractions was raised throughout the whole time of observation (300-600% of the control value). Most of the 14C-glucose was incorporated into the glyceride glycerol fraction.

Adipose Tissue↗

Alterations in phospholipid biosynthesis by polychlorinated biphenyls and polychlorinated biphenylols.

Inhibition and stimulation of synthesis of phospholipids by polychlorinated biphenyls (PCB) have been reported by several authors. The mode of action of PCB on the synthesis of phospholipids has not been determined. Results of experiments in the present report indicate that both PCB and polychlorinated biphenylols alter the activities of key enzymes of glyceride and phospholipid synthesis. 4-Chloro-4-biphenylol (CB-OH), 2',3',4',5,5'-pentachlorobiphenylol (PCB-OH) and 2,4,5,2',4',5'-hexachlorobiphenyl (HCB) inhibited sn-glycerol-3-phosphate acyltransferase activity. Inhibition by PCB-OH was noncompetitive with apparent Ki of 2.6 X 10(-4) M. PCB-OH stimulated phosphatidase activity, but no apparent change was observed with CB-OH. PCB inhibited phosphorylcholine glyceride transferase activity, but had no significant effect on diglyceride acyl transferase.

Acyltransferases↗

Interactions of high density lipoproteins with very low and low density lipoproteins during lipolysis.

Interactions of high density lipoproteins (HDL) with very low (VLDL) and low (LDL) density lipoproteins were investigated during in vitro lipolysis in the presence of limited free fatty acid acceptor. Previous studies had shown that lipid products accumulating on lipoproteins under these conditions promote the formation of physical complexes between apolipoprotein B-containing particles (Biochim. Biophys. Acta, 1987. 919: 97-110). The presence of increasing concentrations of HDL or delipidated HDL progressively diminished VLDL-LDL complex formation. At the same time, association of HDL-derived apolipoprotein (apo) A-I with both VLDL and LDL could be demonstrated by autoradiography of gradient gel electrophoretic blots, immunoblotting, and apolipoprotein analyses of reisolated lipoproteins. The LDL increased in buoyancy and particle diameter, and became enriched in glycerides relative to cholesterol. Both HDL2 and HDL3 increased in particle diameter, buoyancy, and relative glyceride content, and small amounts of apoA-I appeared in newly formed particles of less than 75 A diameter. Association of apoA-I with VLDL or LDL could be reproduced by addition of lipid extracts of lipolyzed VLDL or purified free fatty acids in the absence of lipolysis, and was progressively inhibited by the presence of increasing amounts of albumin. We conclude that lipolysis products promote multiple interactions at the surface of triglyceride-rich lipoproteins undergoing lipolysis, including physical complex formation with other lipoprotein particles and transfers of lipids and apolipoproteins. These processes may facilitate remodeling of lipoproteins in the course of their intravascular metabolism.

Apolipoproteins↗

Influence of castration and testosterone propionate on prostatic and seminal vesicular lipids in mature monkeys.

The effect of castration and administration of testosterone propionate (TP) has been studied in mature monkeys in relation to prostatic and seminal vesicular lipids to castrates on prostatic and seminal vesicular lipids were studied in mature monkeys. Castration decreased prostatic total lipid, total phospholipids and total glyceride glycerols. Among neutral lipid classes only diacyl glycerol was decreased due to castration. Similarly among phospholipid classes, phosphatidyl choline and ethanolamine were decreased. A marked decrease in the seminal vesicular total lipid, total phospholipids, total cholesterol and total glyceride glycerol were observed due to castration. Mono and diacyl glycerols and phosphatidyl choline and ethanolamine also registered a significant decrease after castration. Administration of TP to castrates brought back all the lipid classes to normal level which showed a decrease due to castration. However, TP treated to castrates on both seminal vesicles and prostates had no effect on other classes of lipids which were unaltered by castration. The present study reveals that lipid metabolism in the male accessory sex organs is under androgenic control. Nevertheless, the influence of testicular androgen is specific to different classes of lipids as a number of phospholipids and neutral lipid classes were resistant to castration or administration of TP.

Animals↗

Effects of insulin on the utilization of 14C-glycerol and 14C-glucose in hepatectomized nephrectomized rats.

Insulin (i.v.) administration to functionally hepatectomized-nephrectomized rats did not alter circulating levels of glycerol and only slightly affected plasma radioactivity when animals received (U-14C)-glycerol, whereas after (U-14C)-glucose administration insulin enhanced hypoglycemia and greatly accelerated the rate of radioactivity loss from plasma. At 15 min after i.v. injection of (U-14C)-glycerol, radioactivity in total lipids was reduced in heart and lungs by insulin administration and enhanced in carcass and brown adipose tissue. These effects involved the 14C-glyceride glycerol fraction in the case of heart and 14C-fatty acids in carcass and adipose tissue. When (U-14C)-glucose was administered, insulin enhanced the appearance of 14C-water-soluble material in heart and carcass and 14C-total lipids in heart, carcass, and both brown and white adipose tissue. The effect in heart corresponded mainly to the 14C-glyceride glycerol fraction whereas it corresponded to the 14C-fatty acids in the other tissues. Therefore, insulin effects on glycerol metabolism substantially differ from those on glucose. Opposite effects on heart and lung glycerol utilization as compared to those in carcass and brown adipose tissue may account for the difficulties in observing changes in plasma glycerol levels after insulin treatment.

Adipose Tissue↗