triolein and tripalmitin

α-Cyclodextrin (α-CD), a soluble dietary fiber, may improve abnormal plasma lipids and promote weight loss. Preliminary evidence suggests that it may exert these effects by binding dietary fat and reducing absorption; this has not been tested in humans.. The primary objective was to test whether supplemental α-CD increases fecal content of dietary lipid in humans.. This was a randomized, double-blind, placebo-controlled, crossover study completed at the Mayo Clinic. Eight healthy volunteers, 5 premenopausal women and 3 men ages 23-54 y with body mass index (BMI; kg/m2) 18-27, underwent 2 separate study visits with a ≥2-wk washout period. The first morning of each visit volunteers consumed a standardized breakfast (14.5% protein, 27.5% fat, 60% carbohydrate, and 1.5 kcal/mL) containing [14C]tripalmitin and [3H]triolein with 2 g of α-CD or placebo, followed by 2 g of α-CD or placebo per meal for 2 more days. Volunteers consumed 100 g/d of dietary fat. Feces were collected for 72 h after the labeled breakfast to measure radiotracer content and total fecal fat. Radiotracer appearance in plasma TGs was measured at intervals after the labeled meal as a secondary outcome.. Virtually no 3H radiotracer, but an average of ∼20% of the 14C radiotracer was recovered in fecal lipids, with no difference between α-CD and placebo. Total fecal fat content and radiotracer appearance in postprandial plasma TGs did not differ between the α-CD and placebo treatments. Plasma appearance of 14C-TG was 37% ± 14% less (P < 0.0001) than 3H-TG.. α-CD supplementation did not increase loss of dietary lipid in stool or total fecal fat compared with placebo in healthy adults. Greater stool loss and lesser appearance in plasma TGs of tripalmitin-derived [14C] compared with triolein-derived [3H] TGs imply different metabolic handling of these 2 dietary fat tracers. This trial was registered at www.clinicaltrials.gov as NCT03002168.

Topics: Adult; alpha-Cyclodextrins; Breakfast; Carbon Radioisotopes; Cross-Over Studies; Dietary Fats; Dietary Fiber; Double-Blind Method; Feces; Female; Humans; Intestinal Absorption; Male; Middle Aged; Placebos; Triglycerides; Triolein; Tritium

Lipid metabolism studies focus mainly on oxidation and storage but rarely on faecal elimination, which is needed to assess total lipid distribution during the postprandial period. The purpose of the present work was to set up and validate the analysis of lipid tracers in stools, with an aim of later using this methodology in studies of postprandial lipid tracer metabolism. Eight subjects received a mixture of [1,1,1-(13)C3]tripalmitin and [1,1,1-(13)C3]triolein with a fat-rich meal. The nature and amounts of (13)C lipids excreted in stools during 3 days post-dose were determined by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) analysis of fatty acid methyl esters (FAMEs) from total fatty acid (TFA), free fatty acid (FFA) and triacylglycerol (TAG) fractions. The results were expressed as the Cumulative Tracer Recovery of the administered dose (CTR%). The quantities and labelling of FAMEs were higher in FFA than in TAG, indicating that label loss was not due to a lack of digestive lipase activity. The labelling was higher for C16:0 than for C18:1. The CTRs were 7.03 ± 0.77% and 6.87 ± 0.91%, respectively, in TFA and FFA for [1-(13)C] C16:0, while they were 0.60 ± 0.15% and 0.51 ± 0.11% for [1-(13)C] C18:1 (mean ± sem). By studying the kinetics of lipid excretion from subjects, two groups emerged. The first one showed rapid excretion in stool #1, whereas the second showed slower excretion in stools #2-#3. A significant difference was found in the FFA in stool #1 for C16:0 (p < 0.01) and C18:1 (p < 0.05). Individual excretion kinetics showed marked variability. Nevertheless, the CTR over the 3-day study period was substantial and homogenous for all subjects. These results confirm that the assessment of faecal elimination is of great importance when establishing total lipid distribution during the postprandial period and validate the analysis of cumulative tracer loss during 72 h post-tracer ingestion.

Topics: Adult; Carbon Isotopes; Cross-Over Studies; Digestion; Feces; Gas Chromatography-Mass Spectrometry; Humans; Isotope Labeling; Male; Triglycerides; Triolein; Young Adult

We investigate the phase behavior of model ternary triacylglycerol blends, comprising triolein (C

Topics: Crystallization; Triglycerides; Triolein; X-Ray Diffraction

Seven food grade commercially available lipases were immobilized by covalent binding on polysiloxane-polyvinyl alcohol (POS-PVA) hybrid composite and screened to mediate reactions of industrial interest. The synthesis of butyl butyrate and the interesterification of tripalmitin with triolein were chosen as model reactions. The highest esterification activity (240.63 microM/g min) was achieved by Candida rugosa lipase, while the highest interesterification yield (31%, in 72 h) was achieved by lipase from Rhizopus oryzae, with the production of about 15 mM of the triglycerides C(50) and C(52). This lipase also showed a good performance in butyl butyrate synthesis, with an esterification activity of 171.14 microM/g min. The results demonstrated the feasibility of using lipases from C. rugosa for esterification and R. oryzae lipase for both esterification and interesterification reactions.

Topics: Butyrates; Candida; Enzymes, Immobilized; Esterification; Food Technology; Lipase; Rhizopus; Triglycerides; Triolein

Lung surfactant mainly comprises phosphatidylcholines (PC), together with phosphatidylglycerols and surfactant proteins SP-A to SP-D. Dipalmitoyl-PC (PC16:0/16:0), palmitoylmyristoyl-PC (PC16:0/14:0), and palmitoylpalmitoleoyl-PC (PC16:0/16:1) together comprise 75-80% of surfactant PC. During alveolarization, which occurs postnatally in the rat, PC16:0/14:0 reversibly increases at the expense of PC16:0/16:0. As lipoproteins modify surfactant metabolism, we postulated an extrapulmonary origin of PC16:0/14:0 enrichment in surfactant. We, therefore, fed rats (d19-26) with trilaurin (C12:0(3)), trimyristin (C14:0(3)), tripalmitin (C16:0(3)), triolein (C18:1(3)) or trilinolein (C18:2(3)) vs. carbohydrate diet to assess their effects on surfactant PC composition and surface tension function using a captive bubble surfactometer. Metabolism was assessed with deuterated C12:0 (ω-d(3)-C12:0) and ω-d(3)-C14:0. C14:0(3) increased PC16:0/14:0 in surfactant from 12 ± 1 to 45 ± 3% and decreased PC16:0/16:0 from 47 ± 1 to 29 ± 2%, with no impairment of surface tension function. Combined phospholipase A(2) assay and mass spectrometry revealed that 50% of the PC16:0/14:0 peak comprised its isomer 1-myristoyl-2-palmitoyl-PC (PC14:0/16:0). While C12:0(3) was excluded from incorporation into PC, it increased PC16:0/14:0 as well. C16:0(3), C18:1(3), and C18:2(3) had no significant effect on PC16:0/16:0 or PC16:0/14:0. d(3)-C14:0 was enriched in lung PC, either via direct supply or via d(3)-C12:0 elongation. Enrichment of d(3)-C14:0 in surfactant PC contrasted its rapid turnover in plasma and liver PC, where its elongation product d(3)-C16:0 surmounted d(3)-C14:0. In summary, high surfactant PC16:0/14:0 during lung development correlates with C14:0 and C12:0 supply via specific C14:0 enrichment into lung PC. Surfactant that is high in PC16:0/14:0 but low in PC16:0/16:0 is compatible with normal respiration and surfactant function in vitro.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Animals; Chromatography, Gas; Chromatography, High Pressure Liquid; Deuterium; Dietary Carbohydrates; Dietary Fats; Female; Lung; Male; Myristic Acid; Phospholipases A2; Pulmonary Surfactants; Rats; Rats, Sprague-Dawley; Respiration; Spectrometry, Mass, Electrospray Ionization; Surface Tension; Tandem Mass Spectrometry; Time Factors; Triglycerides; Triolein

In the present study the effects of dietary fat with defined fatty acids on lecithin:cholesterol acyltransferase (LCAT) and apoA-1, the two components of HDL that play a major role in reverse cholesterol transport (RCT), were examined. In addition, the expression of scavenger receptor B1 (SR-B1), the receptor involved in the uptake of HDL core lipids, was also determined under the same conditions in rats fed semisynthetic diets supplemented with triolein (TO), tripalmitin (TP) or menhaden oil (MO). Serum LCAT activity [ micro mol CE/(L.h)] was significantly (P < 0.05) higher in rats fed TO (33 +/- 4) compared with those fed TP (23 +/- 3) or MO (21 +/- 1). The levels of hepatic LCAT mRNA and hepatic SR-B1 receptor protein did not differ between rats fed TP and MO. The triolein diet, on the other hand, increased the induction of hepatic LCAT mRNA and hepatic SR-B1 receptor protein 1.5- to 2-fold. Serum HDL cholesterol concentrations differed among all groups and were 1.30 +/- 0.08, 1.17 +/- 0.10 and 0.91 +/- 0.06 mmol/L for TO-, TP- and MO-fed rats, respectively. Serum apoA-1 levels were significantly higher in TO-fed rats than in the other two groups. The data indicate that TO increases the secretion of HDL and its components (apoA-1 and LCAT), and stimulates the production of hepatic SR-B1 receptor protein. Overall, these results suggest that triolein may promote RCT and thus retard the development of atherosclerosis.

Topics: Animals; Apolipoprotein A-I; Body Weight; CD36 Antigens; Dietary Fats; Fish Oils; Gene Expression; Lipoproteins, HDL; Liver; Male; Membrane Proteins; Phosphatidylcholine-Sterol O-Acyltransferase; Rats; Rats, Sprague-Dawley; Receptors, Immunologic; Receptors, Lipoprotein; Receptors, Scavenger; RNA, Messenger; Scavenger Receptors, Class B; Triglycerides; Triolein

The degradation of alpha-tocopherol and the formation of alpha-tocopherol and triacylglycerol oxidation products at high temperatures (150-250 degrees C) over a heating period (0-4 h) for a model system ranging between triolein and tripalmitin were modeled by use of an experimental design. The oxidation products of alpha-tocopherol formed under these conditions were alpha-tocopherolquinone (1 .4-7.7%) and epoxy-alpha-tocopherolquinones (4.3-34.8%). The results indicate a very high susceptibility of alpha-tocopherol to capture peroxyl radicals upon oxidation, leading to the formation of polar tocopherol oxidation products. Both alpha-tocopherolquinone and epoxy-alpha-tocopherolquinones were not stable upon prolonged heating and were further degraded to other unknown oxidation products. The kinetics of alpha-tocopherol oxidation were significantly influenced by the triolein/tripalmitin ratio. By increasing the level of triacylglycerol unsaturation the rate of alpha-tocopherol recovery after heating increased significantly from 2.2 to 44.2% whereas in the meantime triacylglycerol polymerization increased from 0 to 3.7%.

Topics: alpha-Tocopherol; Chromatography, High Pressure Liquid; Epoxy Compounds; Hot Temperature; Models, Chemical; Oxidation-Reduction; Peroxides; Quinones; Triglycerides; Triolein

Stearoyl-CoA desaturase (SCD) is a microsomal enzyme required for the biosynthesis of oleate and palmitoleate, which are the major monounsaturated fatty acids of membrane phospholipids, triglycerides, and cholesterol esters. Two well characterized isoforms of SCD, SCD1 and SCD2, exist in the mouse. Most mouse tissues express SCD1 and 2 with the exception of the liver, which expresses mainly the SCD1 isoform. We found that asebia mice homozygous for a natural mutation of the gene for SCD1 (SCD-/-) are deficient in hepatic cholesterol esters and triglycerides despite the presence of normal activities of acyl-CoA:cholesterol acyltransferase and glycerol phosphate acyltransferase, the enzymes responsible for cholesterol ester and triglyceride synthesis, respectively, in the liver of these mice. Feeding diets supplemented with triolein or tripalmitolein to the SCD-/- mice resulted in an increase in the levels of 16:1 and 18:1 in the liver but failed to restore the 18:1 and 16:1 levels of the cholesterol ester and triglycerides to the levels found in normal mice. The SCD-/- mouse had very low levels of triglycerides in the VLDL and LDL lipoprotein fractions compared with the normal animal. Transient transfection of an SCD1 expression vector into Chinese hamster ovary cells resulted in increased SCD activity and esterification of cholesterol to cholesterol esters. Taken together, our observations demonstrate that the oleoyl-CoA and palmitoleyl-CoA produced by SCD1 are necessary to synthesize enough cholesterol esters and triglycerides in the liver and suggest that regulation of SCD1 activity plays an important role in mechanisms of cellular cholesterol homeostasis.

Topics: Animals; Cholesterol; Cholesterol Esters; Dietary Fats; Esterification; Fatty Acids, Monounsaturated; Glycerol-3-Phosphate O-Acyltransferase; Heterozygote; Homozygote; Liver; Mice; Mice, Mutant Strains; Microsomes, Liver; Oleic Acid; Stearoyl-CoA Desaturase; Sterol O-Acyltransferase; Triglycerides; Triolein

Reversed-phase high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection at 233 nm was used to separate, quantify, and identify the triacylglycerols (TAG) of milk fat that contain conjugated linoleic acid (CLA). The absorbance at 233 nm was substantially due to CLA-TAG (chromatography of some representative TAG devoid of CLA, such as tripalmitin and triolein, showed poor responses at 233 nm, 1/800th that of CLA-TAG). A CLA molar extinction coefficient at 233 nm of 23,360 L mol(-1) cm(-1) and an HPLC UV response factor were obtained from a commercially available cis-9,trans-11-CLA standard. This molar extinction coefficient was only 86% of reported literature values. Summation of all chromatographic peaks absorbing at 233 nm using the corrected response factor gave good agreement with independent determinations of total CLA by gas chromatography and UV spectrophotometry. This agreement allowed quantification of individual CLA-TAG peaks in the HPLC separation of a typical New Zealand bovine milk fat. Three CLA-containing TAG, CLA-dipalmitin, CLA-oleoyl-palmitin and CLA-diolein, were prepared by interesterification of tripalmitin with the respective fatty acid methyl esters and used to assign individual peaks in the reversed-phase chromatography of total milk fat, of which CLA-oleoyl-palmitin was coincident with the largest UV peak. Band fractions from argentation thin-layer chromatography of total milk fat were similarly employed to identify five predominant CLA-TAG groups in total milk fat: CLA-disaturates, CLA-oleoyl-saturates, CLA-vaccenyl-saturates, CLA-vaccenyl-olein, and CLA-diolein.

Topics: Animals; Cattle; Chromatography, High Pressure Liquid; Linoleic Acids; Milk; New Zealand; Spectrophotometry, Ultraviolet; Triglycerides; Triolein

We examined the effects of dietary fats with specific fatty acid compositions, on serum paraoxonase (PON1) activity in rats. Male adult Sprague-Dawley rats were divided randomly into four dietary groups. One group received the control diet [AIN 93M with soybean oil (5 g/100 g diet)], whereas the remaining three groups received the modified control diet supplemented with (15 g/100 g diet) triolein, tripalmitin or fish oil, respectively. After 20 d, blood was obtained after overnight food deprivation and PON1 activity was determined. Serum lipids and lipid components of lipoproteins were also determined. Serum PON1 activity [micromol/(L.min)] was significantly (P: < 0.05) higher in triolein (98 +/- 6) and lower in fish oil (41 +/- 4), compared with tripalmitin-fed rats (63 +/- 11). Serum PON1 activity in tripalmitin-fed rats was comparable to that of controls (67 +/- 9). Serum PON1 activity correlated significantly with serum lecithin:cholesterol acyltransferase (LCAT) activity (r = 0.77, P: < 0.001) and was transported in blood principally in association with the denser subfraction of HDL, very high density lipoprotein (VHDL; d > 1.15 kg/L). Serum PON1 activity correlated strongly with serum lipids as well as lipids of VLDL, HDL and its subfractions. Multiple linear regression analysis, however, showed a significant relationship of serum PON1 activity, principally with the phospholipids of VHDL (r = 0.47, P: < 0.002). These data suggest that the modulation of serum PON1 activity by dietary fat may be mediated via the effect of the specific fatty acids on the synthesis and secretion of VHDL, the subfraction of HDL that transports the majority of PON1 in the blood.

Topics: Animals; Aryldialkylphosphatase; Body Weight; Cholesterol; Dietary Fats; Esterases; Fasting; Fatty Acids; Fish Oils; Lipids; Lipoproteins; Lipoproteins, HDL; Lipoproteins, VLDL; Male; Phospholipids; Rats; Rats, Sprague-Dawley; Triglycerides; Triolein

For indirect evaluation of pancreatic lipase activity in cystic fibrosis, different 13C-labeled triglycerides may be used.. Triglyceride oxidation in patients with cystic fibrosis was investigated after administration of different 13C-labeled triglycerides by comparing 13CO2 breath exhalation. In the comparative study, five patients with cystic fibrosis (age, 8-15 years; body weight, 22.5-39.8 kg) were treated with Pangrol (individual dosages: 1-3 capsules per morning meal; Berlin-Chemie, Berlin, Germany). [1,1,1-13C3]Glyceryl tripalmitate and [1,1,1-13C3]glyceryl trioleate were administered as a single oral pulse at 8:00 A.M. (dosage, 4 mg/kg each) with the standard diet Fresubin (dosage, 10 ml/kg; Fresenius, Bad Homburg, Germany). Alternately, the same subjects were given the synthetic mixed triglyceride 1,3-distearyl, 2[13C]octanoyl glycerol (dosage, 12.5 mg/kg) contained in the standard diet Nutri-Mix (dosage, 10 ml/kg; Nutricia, Zoetemeer, The Netherlands). Breath samples were taken in 15- and 30-minute intervals over 8 hours. The 13CO2 enrichment was measured by continuous-flow isotope ratio mass spectrometry.. After administration of the 13C-labeled tripalmitin-triolein mixture and the mixed triglyceride, mean maximum 13CO2 enrichments were 4.70 and 7.37 delta over baseline, occurring at 7.0 and 3.5 hours, respectively. The corresponding percentage cumulative 13CO2 exhalations were 12.25% and 29.19%, respectively, and differed significantly in the five paired subjects (p = 0.003).. After using different 13C-labeled triglycerides the resultant 13CO2 exhalation reflected the triglyceride hydrolysis and subsequent oxidation. It is concluded that the different cumulative 13CO2 exhalations were mainly caused by the rate-limiting step of triglyceride hydrolysis to free fatty acids and 2-monoglycerides and by fat deposition. Noninvasive 13C breath tests using different 13C-labeled triglycerides can be used for evaluation of pancreatic lipase activity before and during enzyme supplementation.

Topics: Adolescent; Breath Tests; Carbon Dioxide; Carbon Isotopes; Child; Cystic Fibrosis; Diet; Female; Food, Formulated; Humans; Lipase; Male; Mass Spectrometry; Oxidation-Reduction; Pancreas; Triglycerides; Triolein

While it is well established that the fatty acid composition of dietary fat is important in determining plasma lipoprotein cholesterol concentrations, the effects of changing the absolute quantities of the individual fatty acids are less clear. In the present study Golden Syrian hamsters were fed on isoenergetic, low cholesterol (0.05 g/kg) diets containing 100, 150 or 200 g added fat/kg. This consisted of triolein (TO) alone, or equal proportions of TO and either trimyristin (TM), tripalmitin (TP) or tristearin (TS). Each trial also included a control group fed on a diet containing 50 g TO/kg. As the mass of TO in the diet increased, plasma VLDL-cholesterol concentrations rose. The TM-rich diets produced a concentration-dependent increase in total plasma cholesterol which was a result of significant increases in both VLDL and HDL levels. The TP-rich diets increased plasma LDL- and HDL-cholesterol levels in a concentration-dependent manner. TS-containing diets did not increase the cholesterol content of any of the major lipoprotein fractions. Hepatic LDL-receptor mRNA concentrations were significantly decreased in animals fed on TP, while apolipoprotein B mRNA concentrations were significantly increased. Thus, on a low-cholesterol diet, increasing the absolute amount of dietary palmitic acid increases LDL-cholesterol more than either myristic or stearic acid. These effects on lipoprotein metabolism may be exerted through specific modulation of the expression of the LDL receptor and apolipoprotein B genes.

Topics: Animals; Apolipoproteins B; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Cholesterol, VLDL; Cricetinae; Diet; Fatty Acids; Lipoproteins; Liver; Male; Mesocricetus; Receptors, LDL; RNA, Messenger; Triglycerides; Triolein

Reduced endothelium-derived nitric oxide (NO) production characterizes several vascular diseases. This study examined the effect of triglyceride on NO production induced by endothelin-3 (ET-3) in cultured human umbilical vein endothelial cells. Triglyceride-rich human plasma obtained after a high-carbohydrate diet with white wine was used in an ex vivo study. The plasma triglyceride fraction was found to consist of large amounts of palmitic and oleic acids detected by gas-liquid chromatography. Therefore, the effect of synthetic tripalmitin and triolein emulsion on NO production was also examined. ET-3 stimulated NO and guanosine 3',5'-cyclic monophosphate production and increased cytosolic Ca2+ levels in the endothelial cells (ECs). After incubation of the ECs with the triglyceride-rich plasma for 2 h, these responses to ET-3 were ameliorated in a triglyceride concentration-dependent manner (50-200 mg/dl). A synthesized emulsion of tripalmitin (100 mg/dl) and triolein (100 mg/dl) also blunted the responses to ET-3. Neither endothelial constitutive NO synthase mRNA expression nor its protein level was affected by treatment with triglycerides. These results suggest that triglyceride suppresses ET-3-induced NO synthesis in human ECs by inhibiting cytosolic Ca2+ elevation.

Topics: Blotting, Northern; Blotting, Western; Calcium; Cell Line; Cyclic GMP; Endothelin-3; Endothelium, Vascular; Humans; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type III; Triglycerides; Triolein

Topics: Analysis of Variance; Animals; Cholesterol, Dietary; Cholesterol, LDL; Cricetinae; Dietary Fats; Liver; Male; Mesocricetus; Transcription, Genetic; Triglycerides; Triolein

The effect of dietary fat on hepatic microsomal triglyceride transfer protein(MTP) large subunit mRNA levels in the hamster was examined. Increasing the dietary fat concentration from 11.7 energy % to 46.8 energy % caused a 60% increase in hepatic MTP mRNA; this increase was shown to be dose-dependent (r = 0.688 p = 0.0023). MTP mRNA levels correlated significantly with several plasma lipoprotein cholesterol parameters. No significant relationship was observed between MTP mRNA and either plasma or VLDL triglyceride. The nature of the dietary fatty acids also influenced MTP mRNA levels, with trimyristin and tripalmitin enriched diets significantly elevating MTP mRNA relative to diets enriched in triolein and trilinolein.

Topics: Animals; Carrier Proteins; Cholesterol Ester Transfer Proteins; Cricetinae; Dietary Fats; Energy Intake; Gene Expression Regulation; Glycoproteins; Male; Mesocricetus; Microsomes, Liver; RNA, Messenger; Triglycerides; Triolein

Orlistat, a selective inhibitor of gastrointestinal lipases, was used to investigate triacylglycerol absorption. Using mice and a variety of emulsified dietary lipids we found that the absorption of radiolabelled tripalmitin (containing the fatty acid 16:0), but not of triolein (18:1n-9) or tri-gamma-linolenin (18:3n-6), was incomplete from meals rich in esterified palmitate. Further, the absorption of radiolabelled tri-gamma-linolenin, from both saturated and unsaturated dietary triacylglycerols, was 1.3- to 2-fold more potently inhibited by orlistat than that of triolein and tripalmitin. These radiolabelled triacylglycerols, which have the same fatty acid in all three positions, may not always be accurate markers of the absorption of dietary triacylglycerols. Orlistat was more effective at inhibiting the absorption of radiolabelled triacylglycerols with which it was codissolved than those added separately, which indicates that equilibration between lipid phases in the stomach may not always be complete. The saturation of the dietary lipid had little or no effect on the potency of orlistat. Orlistat provides a novel approach for studying the role of triacylglycerol hydrolysis in the overall process of triacylglycerol absorption.

Topics: Animals; Carbon Radioisotopes; Dietary Fats; Female; Hydrolysis; Intestinal Absorption; Lactones; Lipase; Mice; Mice, Inbred Strains; Orlistat; Triglycerides; Triolein

A triglyceride analog, glycerol-2-palmitoyl-1,3-di-15-(p-iodophenyl)pentadecanoate (DPPG) was synthesized and radiolabeled for evaluation as a potential functional liver scintigraphic agent. Uptake of DPPG was compared in normal, diabetic, tumor-bearing and heparin pretreated rats, revealing differences in uptake and clearance of radioactivity, correlating with hepatic lipase activity of these groups. Similar results were observed by gamma-camera scintigraphy. Comparing the uptake of DPPG with that of its fatty acid component, 15-(p-iodophenyl)pentadecanoic acid (IPPA), revealed that the peak uptake of IPPA in the liver was about half that of DPPG. Based upon these findings, DPPG warrants further study as a hepatic radiodiagnostic agent.

Topics: Animals; Diabetes Mellitus, Experimental; Dogs; Evaluation Studies as Topic; Female; Gamma Cameras; Humans; Iodine Radioisotopes; Iodobenzenes; Lipase; Lipoproteins; Liver; Models, Biological; Neoplasms; Phosphatidylglycerols; Radionuclide Imaging; Rats; Rats, Inbred Strains; Tissue Distribution; Triglycerides; Triolein

The goal of the present study was to determine 1) whether the poor digestion and absorption of glycerol tristearate (TS) that we observed previously is due to amount fed and 2) whether the digestion, absorption, and lymphatic transport of TS is affected by the presence of either a saturated fat [glycerol tripalmitate (TP)] or a monounsaturated fat [glycerol trioleate (TO)]. Three groups of intestinal lymph fistula rats were used. Group A was fed a lipid emulsion containing 12.5 mumol of TS (labeled as [glyceryl-1,3-14C]tristerate), 7.8 mumols of egg phosphatidylcholine, and 57 mumols of sodium taurocholate in 3 ml of phosphate-buffered saline per hour for 8 h. Group B rats were fed the same emulsion as group A, but with 12.5 mumols of TO added. Group C rats had 12.5 mumols of TP instead of TO added to the group A emulsion. The lymphatic radioactivity and triglyceride outputs were significantly lower in group A, with group C next and group B having the highest outputs. Significantly more TS remained in the lumen of the group A rats compared with groups B and C. The majority of the radioactivity in the lumen was still in the TS form in all three groups, indicating poor lipolysis. However, once the fatty acid and monoglyceride were absorbed, the reesterification process was similar in all three groups. When we studied the ability of the three groups of animals to transport the absorbed lipid into lymph (lymph transport index), both groups B and C were significantly better than group A rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Chromatography, High Pressure Liquid; Chylomicrons; Fatty Acids; Intestinal Absorption; Intestinal Mucosa; Intestines; Lipid Metabolism; Lipoproteins, VLDL; Lymph; Lymphoid Tissue; Male; Phospholipids; Rats; Rats, Inbred Strains; Tissue Distribution; Triglycerides; Triolein

Interactions of carbonyl 13C-enriched triacylglycerols (TG) with phospholipid bilayers [egg phosphatidylcholine (PC), dipalmitoylphosphatidylcholine (DPPC), and an ether-linked phosphatidylcholine] were studied by 13C NMR spectroscopy. Up to 3 mol % triolein (TO) or tripalmitin (TP) was incorporated into DPPC vesicles by cosonication of the TG and DPPC at approximately 50 degrees C. NMR studies were carried out in a temperature range (30-50 degrees C) in which pure TO is a liquid whereas pure TP is a solid. In spectra of DPPC vesicles with TG at 40-50 degrees C, both TO and TP had narrow carbonyl resonances, indicative of rapid motions, and chemical shifts indicative of H bonding of the TG carbonyls with solvent (H2O) at the aqueous interfaces of the vesicle bilayer. Below the phase transition temperature of the DPPC/TG vesicles (approximately 36 degrees C), most phospholipid peaks broadened markedly. In DPPC vesicles with TP, the TP carbonyl peaks broadened beyond detection below the transition, whereas in vesicles with TO, the TO carbonyl peaks showed little change in line width or chemical shift and no change in the integrated intensity. Thus, in the gel phase, TP solidified with DPPC, whereas TO was fluid and remained oriented at the aqueous interfaces. Egg PC vesicles incorporated up to 2 mol % TP at 35 degrees C; the TP carbonyl peaks had line-width and chemical shift values similar to those for TP (or TO) in liquid-crystalline DPPC. TO incorporated into ether-linked PC had properties very similar to TO in ester-linked PC.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Emulsions; Lipid Bilayers; Magnetic Resonance Spectroscopy; Models, Theoretical; Molecular Conformation; Phosphatidylcholines; Triglycerides; Triolein

Adult male rats were fed a semi-purified diet containing 20 p. 100 of lard or homogeneous triglycerides (tripalmitin, tristearin, triolein, trierucin) for 4 months. The rates of the processes (absorption, synthesis, degradation into bile acids, fecal and urinary excretion) involved in cholesterol turnover were measured using the isotope equilibrium method. The absorption coefficient of dietary cholesterol attained 71 +/- 3 p. 100 in rats fed the lard diet. It was unchanged in rats eating the triolein (73 +/- 3 p. 100) or tripalmitin (75 +/- 4 p. 100) diet but was drastically reduced in those receiving trierucin (45 +/- 1 p. 100) or tristearin (34 +/- 1 p. 100). Some functional and topological aspects of cholesterol absorption are discussed. Four to 6 times more endogenous cholesterol was found in the intestinal lumen of rats fed trierucin than in that of rats receiving a normolipid diet. Micelle cholesterol increase was also proportionally less. There was no direct relationship between the quantity of cholesterol found in the micelles and that absorbed. Dietary cholesterol was absorbed in the second as well as in the first half of the intestine, while the proportions of micellar cholesterol decreased continuously from the jejunum to the ileum. The rates of fecal excretion and fecal external secretion were inversely correlated to the absorption coefficient of dietary cholesterol, as has been previously described. The internal secretion was stimulated two to threefold in rats fed tristearin (22.3 +/- 0.7 mg/d), tripalmitin (28.4 +/- 4.6 mg/d) and trierucin (33.2 +/- 2.8 mg/d) as compared to rats fed lard (12.5 +/- 0.6 mg/d) or triolein (14.4 +/- 1.2 mg/d). Feeding a tripalmitin or a trierucin diet greatly increased cholesterogenesis (probably in the liver), while tristearin stimulated non-hepatic cholesterogenesis. The variations in daily bile acid elimination may be seen as an adaptive parameter, modulating its rate according to the cholesterol supply (absorption and synthesis).

Topics: Animals; Cholesterol; Dietary Fats; Erucic Acids; Feces; Intestinal Absorption; Intestinal Mucosa; Male; Rats; Rats, Inbred Strains; Tissue Distribution; Triglycerides; Triolein

Topics: Emulsions; Fats, Unsaturated; Iodine; Radioisotopes; Triglycerides; Triolein