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PubMed1976

Fatty acids incorporation into human adipose tissue in hypertriglyceridaemia.

The fatty acid and glucose incorporation into glycerides and glycerol release from adipose tissue were determined in a middle-aged population of 109 men and 41 women. 43 men and 19 women were normolipidaemic. The same analysis was also carried out in 13 male and 9 female normolipidaemic students. Needle biopsy specimens of adipose tissue were incubated in vitro in an albumin medium containing 3H-fatty acids and 14C-glucose. After two hours of incubation values for fatty acid and glucose incorporation were calculated from the incorporation of 3H-activity into the fatty acids and 14C-activity into the glycerol moiety of extracted glycerides. The mean values for fatty acid incorporation were lower in all types of hypertriglyceridaemic subjects (II B, III, IV and V) than in the normolipidaemic control subjects. In the male hypertriglyceridaemic population 36% had values for fatty acid incorporation below the 5th percentile of the normolipidaemic group and 14% had values below the lowest normal value. The rate of fatty acid incorporation was negatively correlated with the serum triglyceride concentration. This correlation remained unchanged when partial correlation was performed when the influence of body weight was eliminated. Fatty acid and glucose incorporation correlated positively. Incorporation of glucose behaved in the same way as described above for incorporation of fatty acids. Glycerol and fatty acid release was the same in the normo- and hypertriglyceridaemic groups. It is likely that the removal of plasma triglycerides from blood requires hydrolysis of triglycerides to fatty acids and the subsequent removal of the fatty acids. The hypothesis has been formulated that when the former process is normal, a defect of fatty acid removal (a low rate of fatty acid incorporation into glycerides) may be responsible for an impaired removal of plasma triglyceride-fatty acids. A low rate of fatty acid incorporation may contribute to the development of hypertriglyceridaemia, according to this hypothesis.

Adipose Tissue↗
PubMed1983

Characteristic constituents of glycolipids from frog brain and sciatic nerve.

Cerebroside, sulfatide, monoglycosyl glyceride, and ester cerebroside were isolated from frog brain and sciatic nerve, and their distribution and chemical constituents were determined. The long-chain base compositions of cerebroside, sulfatide, and ester cerebroside were unique in the presence of branched-base components (5-15% of the total bases) and in the abundance of saturated dihydroxy base components (15-45% of the total). The amount of branched long-chain bases was greater in sciatic nerve than in brain. The hexose composition of the glycolipids consisted entirely of galactose except for brain cerebroside, in which a small amount of glucose was detected. Monogalactosyl glyceride consisted of the diacyl and alkylacyl forms, in a molar ratio of 81:19 for brain and 62:38 for sciatic nerve. The fatty acid composition of glycosphingolipids was characterized by the predominance of hydroxy and nonhydroxy 24:1 acids, and the concentration of 24:0 was extremely low. The proportion of unsaturated fatty acids accounted for 80% of the total. Major fatty acids of monogalactosyl glyceride were palmitic, oleic, stearic, and palmitoleic acids; the highest concentration was that of palmitic acid. Ester cerebroside was separated into three subfractions mainly on the basis of the proportion of hydroxy and nonhydroxy components in the amide-linked fatty acids.

Animals↗
PubMed1978

Gastric ulceration and the concentration of salicylate in plasma in rats after administration of 14C-labelled aspirin and its synthetic triglyceride, 1,3-dipalmitoyl-2(2'-acetoxy-[14C]carboxylbenzoyl) glycerol.

Triglycerides containing aspirin in place of one or more fatty acid residues of the molecule have been synthesized. Metabolism of the compound with the labelled (14C) drug residue introduced specifically into the 2-position of the triglyceride is reported. Plasma salicylate concentrations with this synthetic glyceride were determined and compared with those obtained with commercially available aspirin labelled with the 14C-isotope. Both compounds gave a therapeutic concentration of salicylate in the plasma after ingestion. The 1,3-di-fatty acyl-2-aspirin glyceride was absorbed through the intestine as 2-aspirin monoglyceride, some 20% of which was transported through the thoracic-duct chyle and about 30% through the portal system. Whereas pronounced ulceration of the rat stomach occurred with free aspirin, the above fatty acyl glyceride of aspirin produced no ulceration.

Animals↗
PubMed1980

Selective inhibition by neuraminidase of insulin action on hexose metabolism of mouse adipocytes.

Mouse adipocytes treated with neuraminidase showed a decreased response of glucose oxidation to insulin although insulin binding to the cells was normal. The decreased response was associated with the release of sialic acids from the cells by enzyme digestion. The hormone action on 2-deoxyglucose uptake was also decreased. However, the hormone action on glyceride-glycerol synthesis or lipogenesis from glucose was unaltered when enzyme-treated cells were incubated with higher glucose concentration (greater than or equal to 5 mM). However, at lower glucose concentrations (< 5 mM), in which glucose transport was a rate-limiting step, the hormone action was markedly decreased. When fructose was used as a substrate, the enzyme-treated cells showed an impaired response to insulin in fructose oxidation but not in glyceride-glycerol synthesis and lipogenesis from fructose. These results suggest that the postreceptor systems of insulin action on glyceride-glycerol synthesis and lipogenesis from hexose are different from those of the hormone action on hexose transport and oxidation. Furthermore, alteration in insulin-sensitive metabolic profiles may be caused, in part, by changes in glycoproteins and/or glycoplipids on the cell surface.

Adipose Tissue↗
PubMed1998

Influence of different fat emulsions with 10 or 20% MCT/LCT or LCT on lipoproteins in plasma of patients after abdominal surgery.

In patients after elective abdominal surgery, different fat emulsions were used to compare their efficacy in total parenteral nutrition and in normalizing plasma lipoprotein levels. In five different groups with 5 patients each, half of the nonprotein calories were given as medium-chain triglycerides/long-chain triglycerides (1:1) or as long-chain triglycerides alone in 10 or 20% fat emulsions or as glucose alone in a control group for 7 days. After surgery, an initial decrease of all plasma lipoprotein components was followed by a different behavior of glyceride-glycerol, cholesterol, phospholipids, and apolipoproteins. Glyceride-glycerol in very-low-density lipoproteins and high-density lipoproteins is increasing during infusion of fat emulsions and decreasing during overnight interruption of infusions. After the 7-day infusion period, there was no significant difference in very-low-density lipoprotein glyceride-glycerol as compared with the values before different infusions. Low-density lipoprotein cholesterol is reaching and exceeding preoperative concentrations between the 4th and the 7th day, most during infusion of 10% fat emulsion and especially due to an increase of free cholesterol. High-density lipoprotein cholesterol and apolipoprotein A-I reach preoperative levels during infusion of fat emulsions but not with glucose alone. Higher than preoperative values are reached in phospholipids with all fat infusions already on day 4. Abnormal lipoprotein X occurred least with the medium-chain/long-chain triglyceride 20% fat-infusion. This fat emulsion is suggested as having the best normalizing effect on plasma lipoproteins and best tolerance in patients after surgery.

Abdomen↗
PubMed1968

Studies on the turnover of triglyceride and esterified cholesterol in subjects with the nephrotic syndrome.

Factors involved in the hyperlipidemia of nephrosis have been studied in seven patients. The turnover of triglyceride was measured in plasma very low density lipoproteins after the injection of glycerol-(14)C. The turnover of esterified cholesterol was measured in whole plasma and in very low density lipoproteins after the injection of mevalonic acid-2-(3)H. Urine protein loss was found to be significantly correlated with the plasma concentrations of triglyceride and free cholesterol, suggesting that increasing loss of protein is associated with the formation of larger lipoproteins. Lactescent plasmas were found in the subjects with the greatest protein loss. The turnover rate of triglyceride tended to be higher among subjects with higher than with lower triglyceride concentrations and was on the average higher than among six normotriglyceridemic subjects. However, there was also evidence for decreased clearance of glyceride from plasma. The hypertriglyceridemia of nephrosis appeared to reflect both increased formation of glyceride and decreased removal of glyceride from plasma. The turnover of esterified cholesterol was significantly higher in whole plasma of nephrotic subjects than in normocholesterolemic nonnephrotic patients. Esterified cholesterol turnover in very low density lipoproteins was raised in the two subjects in whom a major part of total esterified cholesterol was carried in this lipoprotein fraction. These studies were repeated in one subject after remission was induced. The cessation of urinary loss of protein was associated with reductions in the concentrations and turnover of triglyceride and esterified cholesterol. The increased turnover of plasma lipids in nephrosis may reflect the general increase in the formation of protein.

Adolescent↗
PubMed1976

Effects of riboflavin deficiency on the lipids of rat liver.

Newly weaned male rats were maintained on a riboflavin-free diet for 5 weeks, and a study was made on the effect of the deficiency upon liver lipids. The content of glyceride in the livers varied among the deficient rats. High contents of glyceride were demonstrated in one-third of the deficient rats, whereas the similar level as that of control was shown in the remaining deficient rats. Contents of phospholipids and relative amounts of individual phospholipids were not altered significantly by the deficiency. Riboflavin deficiency exerted effects on fatty acid components of liver lipids. The composition of fatty acids of triglycerides varied in the deficient rats depending on the content of glycerides. However trends of increase in linoleic acid and decrease in palmitic acid towards fatty liver were observed in the deficiency in comparison with the control. On the other hand, the changes in phospholipid fatty acids were similar in all deficient rats, and the increase in linoleic acid and the decrease in arachidonic acid were brought about by the deficiency compared with controls, respectively. In liver homogenates, the incorporation of 14C-palmitate into triglycerides was higher in the deficient rats irrespective of the presence or absence of fluorde but incorporation into phospholipids was slightly lower in the deficient rats than in control animals.

Animals↗
PubMed1976

[Tolerance and metabolic results of long-term administration of a mixture of saturated triglycerides by recto-colic route in rabbits].

Rabbit's and Dog's colonic absorption of triglycerides is shown in previous works. Further, we are studying the possibility to use the rectal route for nutritive substances. This way remains now poorly used and an exceptional therapeutic. However, bringing triglycerides in adequate state would be an energetic, supply, all the more as it is very difficult to provide potent caloric source in parenteral nutrition. This is why we investigate, on the Rabbit, the issues of chronic administration of glycerides by rectal route, on caloric balance and on a biochemical view to seek for in lipid composition of tissues the print of lipids administrated by transanal way. The animals are individually housed in metabolism units feeding a standard diet and drinking ad libitum. The treated subjects are given by transanal way, twice a day, for eight weeds, a sum of 1 g/kg of medium chain triglycerides. The metabolic balance-sheet is daily drawn. The clinic balance-sheet is set on the end, by biological controls to explore the hepatic and renal function (prothrombine ratio, transaminases (SGOT, SGPT), ornithine, carbamyl transferase (OCT), urea, total proteins ratio and electrolyte imbalance. We measure also the concentration of total lipids plasma and tissue (liver, kidney, heart, lungs, perirenal adipose tissue). The triglyceride composition and fatty acid composition of different lipids fractions of control and treated subjects are analyzed by gas-liquid chromatography. The animals support perfectly, without damage, a chronic and massive (1 g/kg/each day) administration of medium chain triglycerides by rectal route. The growth of treated subjects is normal. On the opposite, they adjust their alimentary consumption with the caloric charge of the diet, this is the reason why the reduction is about 12p. 100 with respect to the control animals. The coli-rectal administration of saturated glycerides produces at middle end only qualitative variations of lipids extracts. They essentially affect the triglyceride and fatty acid fraction of the tissue lipids, they become intermediate between that of control animals and the mixture administered by the transanal way. These results prove the integration of the glycerides in the metabolic pathway. They show the problem of the colonic absorption for the liposoluble substances. They authorize researches in view of a possible caloric assistance by this way.

Animals↗
PubMed1991

[Biodegradable gentamicin-depot implants made of beta-tricalcium phosphate ceramics. 3. In vivo studies on drug release, tissue tolerance, and biodegradation].

In vivo drug release properties and biocompatibility of gentamicin-loaded controlled release implants made of beta-tricalcium phosphate ceramics designed for the local antibiotic treatment of bone infections were investigated. Controlled release pellets containing 0.4 and 0.8 mg of gentamicin were implanted into the femoral bone of rats. Drug release was measured from renal excretion over a time period of 3 weeks. The excretion pattern can be described by an initial phase of increased drug release was faster at higher drug loading. Drug release from glyceride-containing controlled release pellets occurs at a significantly slower rate than from drug-loaded pellets without glycerides. Histological studies after implantation of the pure ceramic pellets and the controlled release pellets into the bone tissue of rats and rabbits are showing a high tissue tolerance and the biodegradability of the implants. However, the glyceride-containing pellets are degraded at a slower rate than the pure ceramic pellets.

Animals↗
PubMed1989

[Future perspectives in parenteral nutrition].

Some of the future perspectives of parenteral nutrition will most likely be related to the possibilities of improving the infusion solutions used. There are studies indicating that intravenous amino acid mixtures may produce better biochemical and clinical effects either by increasing the content of histidin, arginine, tyrosine, cysteine/cystine and branched chain amino acids or by adding glutamine, ornithin, ornithin-ketoglutaric acid, taurine and glutathion. Several possibilities of improving the intravenous fat emulsions have been studied and discussed. The use of medium chain fatty acid glycerides (MCT) instead of long chain fatty acid glycerides (LCT) may be of some value. Physical mixtures of LCT and MCT have been studied. Glycerides of both medium chain and long chain fatty acids of the same glycerol molecule ('structured lipids') have also been investigated. The omega-3-fatty acids (alfalinolenic, eicosapentaenoic and docosahexaenoic acid) have unique biochemical properties which may be beneficial in various clinical situations when parenteral nutrition is indicated. Intravenous fat emulsions containing triglycerides of these fatty acids are now being extensively investigated. The omega-3-fatty acids will change the pattern of eicosanoids formed, reduce the tendency to platelet aggregation, increase the resistance to endotoxins, and reduce the viscosity of the blood. Triglycerides of gamma linolenic acid have been considered to be of value in situations when there may be a reduced activity of delta-6-desaturase to transform linoleic acid to arachidonic acid. Many other known (carnitine, non-protein sources, vitamins and trace elements) or unknown nutrients may be found to be useful in order to improve the infusion solutions used in parenteral nutrition.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1974

Metabolic patterns and insulin responsiveness of enlarging fat cells.

The rate and pattern of glucose metabolism, basal lipolysis, and intracellular concentration of free fatty acids were determined in isolated epididymal fat cell preparations (mean volume 30-800 pl) from rats on the basis of fat cell number and in relation to the cell volume. The effects of increasing glucose concentrations in the medium and of insulin on the cellular metabolic activities were compared. Expanding fat cell volume correlated positively and significantly (P < 0.001) with the synthesis of glyceride glycerol from glucose (correlation coefficient, r = 0.919), with rates of basal lipolysis (r = 0.663), and with intracellular free fatty acid accumulation (r = 0.796); it correlated negatively and significantly with glucose conversion to glyceride fatty acids (r = -0.814, P < 0.01). The differences in patterns of glucose metabolism and basal lipolysis between small (<100 pl) and large (>400 pl) fat cells were not modified by insulin or by increments in glucose concentration. The results indicate that the reduced capacity of the large fat cells to respond to insulin cannot be attributed solely to a limited capacity of the cells to take up and metabolize increasing amounts of glucose. The acquired unresponsiveness of the large cells to insulin may result from an alteration in the mechanism of action of insulin and may be related to an intracellular metabolic derangement with increased basal lipolysis, free fatty acid accumulation, and accelerated glyceride synthesis resulting from the accumulation of triglyceride.

Adipose Tissue↗
PubMed1967

Effect of propionate on lipogenesis in adipose tissue.

The metabolism of propionate in adipose tissue and its effect on lipogenesis was investigated. Fasting induced changes in propionate metabolism of adipose tissue, drastically reducing higher fatty acid synthesis and increasing glyceride-glyerol formation from low concentrations of propionate (0.25 mM). Propionate also promoted lipogenesis from acetate-1-(14)C in tissues of fasted rats, while it inhibited lipogenesis and CO(2) formation from acetate in the fed animal. Treatment with actinomycin D or ethionine abolished both the increased glyceride-glycerol formation from propionate and the promoting effect on lipogenesis from acetate. Synthesis of long-chain fatty acids from propionate-1-(14)C was increased by actinomycin treatment. The change in propionate metabolism induced by fasting is, however, not entirely due to its conversion to glyceride-glycerol, since the latter was almost completely blocked by malonate while part of the promoting effect on fatty acid synthesis persisted.

Acetates↗
PubMed1978

Evidence for a dual mechanism of lipolysis activation by epinephrine in rat adipose tissue.

Whole homogenates prepared from tissue previously exposed to epinephrine displayed a 3-fold increased rate of lipolysis of endogenous substrate. When the aqueous infranatant phase of such homogenates was collected by centrifugation and assayed against exogenous triolein emulsions, no hormone effect could be demonstrated. Treatment of such infranatants with cAMP-dependent protein kinase prepared from muscle increased their lipase activity against exogenous triolein by 80%. Employing [3H]triolein emulsions as exogenous substrate, rates of lipolysis of both endogenous and exogenous glycerides were measured simultaneously in whole tissue homogenates. Prior treatment of the tissue with epinephrine increased the rate of lipolysis of endogenous glycerides an average of 3-fold but had no effect on the hydrolysis of exogenous triolein. By contrast, treatment of whole homogenates with protein kinase accelerated lipolysis of exogenous triolein without altering the rate of hydrolysis of endogenous glycerides. The data suggest that a second pathway of lipolysis activation occurs in response to epinephrine in addition to that involving a cAMP-mediated increase in the state of phosphorylation of the hormone-sensitive lipase.

Adipose Tissue↗
PubMed1982

Sex differences in adrenocortical structure and function. X. Lipid and corticosterone in the rat adrenal as affected by gonadectomy and testosterone or estradiol replacement.

Studies were performed on lipid and corticosterone content in adrenal glands of intact male and female rats and on their relation to gonadectomy and gonadal hormone replacement. Concentration of total lipid, total cholesterol, phospholipid and glycerides is similar in adrenals of adult male and female rats, however their content, due to larger adrenals, is markedly higher in females. Orchiectomy has no effect on concentration of lipid classes studied while their content in adrenals increased. Testosterone replacement resulted in an increase in concentration of total lipid and phospholipid and has no effect on total cholesterol and glyceride concentration. Ovariectomy evoked an increase in total lipid and phospholipid concentration, has no effect on glycerides and lowered total cholesterol concentration in rat adrenals, while estradiol replacement diminished concentration of all classes of lipids studied. Adrenal corticosterone concentration is higher in female than male rat while no differences in BT-positive steroid were observed. Orchiectomy increased corticosterone concentration, after testosterone administration the value did not differ from control. Ovariectomy has no effect and estradiol increases corticosterone concentration in the gland. Performed studies suggest that testosterone increases the concentration of main classes of lipids and decreases the corticosterone concentration in the rat adrenal cortex while estradiol has an opposite effect.

Adrenal Cortex↗
PubMed1978

Effects of glucose on the metabolization of fructose and glycerol by isolated adipocytes from rat.

Isolated white fat cells were incubated in medium containing (14C)-fructose (UL), supplemented with either 1 or 5 mM fructose, in the presence or absence of 5 mM glucose. The utilization of fructose for the formation of CO2, fatty acids or glyceride glycerol was very much dependent on its concentration in the medium. It was significantly inhibited by glucose only at fructose concentration of 5 mM. When the cells were incubated in the presence of (1(-14)C) glycerol, fructose produced a significant increase in the conversion of the tracer to CO2, fatty acids and glyceride glycerol, while glucose produced an increase in the formation of both CO2 and fatty acids, but a significant decrease of glyceride glycerol from the same labelled precursor. Glucose causes the effects of fructose, enhancing the uptake of labelled glycerol by the cells, to disappear.

Adipose Tissue↗
PubMed1989

Sterically hindered analogues of diacylglycerols. Synthesis, binding to the phorbol ester receptor and metabolism in A549 human lung carcinoma cells.

The 5 following compounds were synthesized in order to investigate the relationship between structure and ability of glyceride-type molecules to bind to the phorbol ester receptor: one dioctanoyl cyclohexane-1,2,4-triol, 2 isomeric methyl analogues of 1,2-dioctanoyl-sn-glycerol (diC8), one dimethyl and one cyclohexyl analogue of diC8. Their ability to compete with 3H-labelled phorbol-12,13-dibutyrate [( 3H]PDBu) for specific binding sites in intact A549 human-derived lung carcinoma cells and in a cytosolic cell extract was compared with that of diC8 and 12-O-tetradecanoylphorbol-13-acetate (TPA). The affinity of diC8 for the phorbol ester receptor was much weaker than that of TPA. The analogues in turn were less able than diC8 to compete with [3H]PDBu for receptor sites. Like diC8 and unlike TPA, the synthesized compounds inhibited cell growth only at those concentrations at which cytotoxicity was also apparent. DiC8 and its methyl and dimethyl derivates, but not the cyclohexyl derivative or the cyclohexanetriol diester, were metabolically removed from cellular incubates as measured by gas liquid chromatography. The results suggest that the binding of glyceride-type molecules to the phorbol ester receptor exhibits stringent specificity and that the design of novel potent agonists of phorbol esters might require the placement of the molecular features of diacylglycerols important for biological activity into a molecular framework which is more complicated than glycerol.

Caenorhabditis elegans Proteins↗
PubMed1986

Effect of carbon and nitrogen sources on the chemical composition of lipids of Rhizopus delemar.

Soy bean extract with glucose or oleic acid in the growth medium of Rhizopus delemar affected the production of higher values of biomass, total lipids and total glycerides than when ammonium nitrate was used as a source of nitrogen. The highest amounts of biomass (12.35 g/l) and total lipids (310 mg/g dry biomass) were attained in glucose-grown mycelia. The high proportions of total glycerides and unsaturated fatty acids in lipids of Rhizopus delemar suggest the utilization of such lipid material for nutritional and industrial purposes.

Carbon↗
PubMed1976

Effect of dietary fats on ovine adipose tissue metabolism.

The effects of different dietary fats on ovine adipose tissue metabolism have been investigated. Six-month old sheep were fed for 6 weeks a control diet or diets supplemented with either tallow or a mixture of sunflower seed oil and soybean oil, treated to protect the fats from hydrolysis and hydrogenation in the rumen, or with maize oil. The rates of fatty acid, glyceride glycerol, and CO2 formation were measured in perirenal and subcutaneous adipose tissue slices by following the incorporation of either 14C from labeled acetate or glucose, or 3H from tritiated water into the appropriate product. Feeding protected tallow or maize oil but not protected sunflower seed oil plus soybean oil resulted in reduced rates of fatty acid biosynthesis in both perirenal and subcutaneous adipose tissue slices and CO2 formation in perirenal adipose tissue. Feeding the fat-supplemented diets had no effect on the rate of glyceride glycerol formation. The fat-supplemented diets also resulted in reduced activities of various enzymes, thought to be involved in lipogenesis, measured in 105,000 x g supernatant fractions from adipose tissue homogenates. The results suggested that ovine adipose tissue lipogenesis is sensitive to both the amount and the nature of dietary fat.

Acetate-CoA Ligase↗