Abstract:
:Lipoprotein lipase has been found to efficiently mediate binding of lipoproteins to cell surfaces and to the low density lipoprotein (LDL) receptor-related protein (LRP) under cell culture conditions (Beisiegel et al. 1991. Proc. Natl. Acad. Sci. USA. 88: 8242-8346). This supports the previously proposed idea that the lipase could have a role in receptor-mediated uptake of chylomicron remnants in the liver. We have investigated the effects of lipoprotein lipase on the clearance of chylomicrons during perfusions of rat livers. The chylomicrons were doubly labeled in vivo with [14C]retinol (in retinyl esters) and with [3H]oleic acid (in triacylglycerols) and were collected from lymph. In the absence of any lipase the clearance of chylomicron label from the perfusion medium was slow. Addition of lipoprotein lipase caused lipolysis of chylomicron triacylglycerols as evidenced by increased levels of 14C-labeled fatty acids in the perfusate. Simultaneously, the level of [14C]retinyl esters in the perfusate decreased dramatically, indicating core-particle removal. Similar effects were seen with an unrelated lipase from Pseudomonas fluorescens. To discriminate between the effects of lipolysis and a true liganding effect of the lipoprotein lipase protein, the active site inhibitors tetrahydrolipstatinR and hexadecylsulfonylfluoride were used to reduce or totally inhibit the catalytical activity. With lipase covalently inhibited by the latter inhibitor, lipolysis during perfusions was low or absent. Nonetheless, the inhibited enzyme had a clear effect on the removal of chylomicrons by the liver. With 1.2 micrograms of inhibited lipase/ml perfusate, about 70% of the core label had been removed after 15 min as compared to about 20% in perfusions without lipase. With identical amounts of active lipoprotein lipase protein, more than 90% of the label was removed. We conclude that any lipase causing lipolysis of chylomicrons can stimulate their clearance by the liver, but that lipoprotein lipase has an additional effect on the removal, which is not dependent on its catalytic activity.
journal_name
J Lipid Resjournal_title
Journal of lipid researchauthors
Skottova N,Savonen R,Lookene A,Hultin M,Olivecrona Gsubject
Has Abstractpub_date
1995-06-01 00:00:00pages
1334-44issue
6eissn
0022-2275issn
1539-7262journal_volume
36pub_type
杂志文章abstract::The absorption and distribution of deuterated trans- and cis-13-octadecenoic acid (13t-18:1 and 13c-18:1) in plasma lipids were compared to deuterated cis-9-octadecenoic acid (9c-18:1) in two young adult male subjects. A mixture of triglycerides was fed in a multiple-labeled experiment where each triglyceride containe...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1983-01-01 00:00:00
abstract::Delta 6 desaturase (FADS2) is a critical bifunctional enzyme required for PUFA biosynthesis. In some organisms, FADS2s have high substrate specificity, whereas in others, they have high catalytic activity. Previously, we analyzed the molecular mechanisms underlying high FADS2 substrate specificity; in this study, we a...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:10.1194/jlr.M079806
更新日期:2018-01-01 00:00:00
abstract::Boiled coffee contains an unidentified lipid that raises serum cholesterol. We studied the effects of the ingestion of coffee oil fractions of increasing purity in volunteers in order to identify the cholesterol-raising factor. In 15 volunteers who ingested 0.75 g/d of a non-triglyceride-fraction from coffee oil for 4...
journal_title:Journal of lipid research
pub_type: 临床试验,杂志文章,随机对照试验
doi:
更新日期:1994-04-01 00:00:00
abstract::To assess the possible role of altered hepatic processing of free fatty acids in dietary sucrose-induced accumulation of triglyceride in the liver and blood plasma, livers from rats fed commercial laboratory stock and high sucrose diets were perfused both with and without oleic acid substrate. Consumption of the sucro...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1987-10-01 00:00:00
abstract::Cerebrosides have been isolated from adult human aortic tissue. Each aorta was divided into portions classified as normal, fatty streaks, fibrous plaques, or complicated lesions. The cerebrosides were isolated by Florisil column chromatography, mild alkaline methanolysis, a second Florisil column, and preparative thin...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1968-07-01 00:00:00
abstract::ABCA12 mutations disrupt the skin barrier and cause harlequin ichthyosis. We previously showed Abca12(-/-) skin has increased glucosylceramide (GlcCer) and correspondingly lower amounts of ceramide (Cer). To examine why loss of ABCA12 leads to accumulation of GlcCer, de novo sphingolipid synthesis was assayed using [(...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:10.1194/jlr.M044941
更新日期:2014-03-01 00:00:00
abstract::In mice, the yolk sac appears to play a crucial role in nourishing the developing embryo, especially during embryonic days (E) 7;-10. Lipoprotein synthesis and secretion may be essential for this function: embryos lacking apolipoprotein (apo) B or microsomal triglyceride transfer protein (MTP), both of which participa...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1999-11-01 00:00:00
abstract::Membrane-protein interaction plays key roles in a wide variety of biological processes. Although various methods have been employed to measure membrane binding of soluble proteins, a robust high-throughput assay that is universally applicable to all proteins is lacking at present. Here we report a new fluorescence que...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:10.1194/jlr.D041376
更新日期:2013-12-01 00:00:00
abstract::We designed a rapid method for determining mRNA content of cholesterol biosynthesis enzymes and LDL receptor (LDLR) using a ribonuclease protection assay (RPA). 32P-labeled cRNA fragments for genes of human LDLR and the enzymes HMG-CoA synthase (HMGS), HMG-CoA reductase (HMGR), mevalonate kinase (MK), farnesyl pyropho...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1995-09-01 00:00:00
abstract::Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) has been applied primarily to the analysis of glycosphingolipids separated from other complex mixtures by TLC, but it is difficult to obtain quantitative profiling of each glycosphingolipid among the different spots on TLC by MALDI-MS. Thus, the ...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:10.1194/jlr.D800038-JLR200
更新日期:2008-12-01 00:00:00
abstract::Lecithin:cholesterol acyltransferase (LCAT) deficiency syndromes represent a group of rare genetic disorders of HDL metabolism that have been the subject of a large number of clinical, biochemical, and genetic studies. Of special interest are patients with LCAT-related disorders with severe HDL deficiency and the appa...
journal_title:Journal of lipid research
pub_type: 杂志文章,评审
doi:
更新日期:1997-02-01 00:00:00
abstract::To study the effect of an unstirred layer (UL), we have investigated the exchange efflux kinetics of anandamide at 0 degrees C, pH 7.3, from albumin-free as well as from albumin-filled human red blood cell ghosts to media of various BSA concentrations ([BSA](o)). The rate constant (k(m)) of unidirectional flux from th...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:10.1194/jlr.M500411-JLR200
更新日期:2006-03-01 00:00:00
abstract::The conversion of alpha-linolenate (18:3n-3) to docosahexaenoate (22:6n-3) in the presence of low and high dietary levels of linoleate (18:2n-6) is reported in young rats using [U-13C]-alpha-linolenic acid (18:2n-3*) and high precision gas chromatography-combustion isotope ratio mass spectrometry (GCC-IRMS). After con...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1995-05-01 00:00:00
abstract::The percentage of saturated cholesteryl esters (CEs) synthesized by human LCAT is several times higher than expected from the sn-2 acyl composition of plasma phosphatidylcholine (PC), whereas the synthesis of 20:4 CE and 22:6 CE is much lower than expected. To explain these discrepancies, we proposed that LCAT transfe...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:10.1194/jlr.M400197-JLR200
更新日期:2004-12-01 00:00:00
abstract::We have previously shown that expression of a human apoE cDNA in J774 macrophages enhances cholesterol efflux to HDL3. We have also shown that endogenous apoE expression produces a cell surface pool of apoE associated with proteoglycans. In this series of experiments, we first demonstrate the presence of a cell surfac...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1998-02-01 00:00:00
abstract::The effects of eicosapentaenoic acid and oleic acid on lipid synthesis and secretion by HepG2 cells were examined to identify fatty acid specific changes in lipid metabolism that might indicate a basis for the hypolipidemic effect attributed to eicosapentaenoic acid and related n-3 fatty acids. Cellular glycerolipid s...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1991-02-01 00:00:00
abstract::Remnant-like emulsions were prepared with lipid compositions similar to remnants derived from triacylglycerol-rich lipoproteins. When injected into the bloodstream of conscious mice the remnant-like emulsions labeled with cholesteryl[13C]oleate were metabolized in the liver and the appearance of 13CO2 in the breath wa...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1998-03-01 00:00:00
abstract::Significant amounts of ursodeoxycholic acid (UDCA) used for the treatment of patients with primary biliary cirrhosis (PBC) become epimerized at C-3 to isoUDCA. We investigated the metabolism of isoUDCA and a possible pharmacologic effect in five patients (51.4 +/- 5.8 years old; 3 females, 2 males) with PBC and persis...
journal_title:Journal of lipid research
pub_type: 临床试验,杂志文章
doi:
更新日期:2001-05-01 00:00:00
abstract::This work describes the molecular mechanisms of fatty acid and hormonal modulations of the retinoid X receptor alpha (RXRalpha) in rat liver cells. We examined the effects of different fatty acids (myristic, stearic, oleic, linolenic, and arachidonic acids, EPA, and the peroxisomal proliferator TTA) and several hormon...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1998-04-01 00:00:00
abstract::Lipogenesis in vitro from acetate-1-(14)C was studied in human preputial skin and abdominal skin. Radioactive lipids were separated by column chromatography on Florisil and by thin-layer chromatography on silica gel. Radioactivity was incorporated chiefly into the triglyceride, sterol, and polar lipid fractions, while...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1969-09-01 00:00:00
abstract::The dynamics of human apoE metabolism were explored by examining the effects of alimentary lipemia and postheparin lipolysis on the plasma level and lipoprotein distribution of apoE. In the studies of alimentary lipemia, fasting and postprandial plasma samples were obtained from five normal adult males, each of whom d...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1982-12-01 00:00:00
abstract::The fatty acid composition of human skin fibroblasts grown in 10% dialyzed fetal calf serum can be modified considerably by adding supplemental fatty acids to the culture medium. The degree of modification was dependent on the concentration of added fatty acid over the range tested, 2.5 X 10(-5) to 1 X 10(-4) M. At th...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1979-05-01 00:00:00
abstract::Acyl-CoA:monoglyceride acyltransferase in microsomal preparations from the small intestine of the rat has been measured by means of continuous recording spectrophotometry. The reaction of 5,5'-dithiobis(2-nitrobenzoic acid) with CoA has been employed for this assay and optimal conditions for the reaction have been def...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1969-07-01 00:00:00
abstract::The selective and reversible adsorption of bovine low density lipoproteins (LDL) by heparin-Sepharose has been exploited as the critical step in a procedure for the preparative isolation of very low density lipoproteins (VLDL)/chylomicrons, LDL, and high density lipoproteins (HDL) from bovine plasma. Molecular size ex...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1985-06-01 00:00:00
abstract::The aim of this study was first to examine the relationships between adiponectin gene (Apm1) polymorphisms and anthropometric indices as well as plasma adiponectin and lipoprotein/lipid levels, and then to investigate whether the presence of visceral obesity or insulin resistance may modulate the impact of these polym...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:10.1194/jlr.M400135-JLR200
更新日期:2005-02-01 00:00:00
abstract::Mitochondrial sterol 27-hydroxylase (EC 1.14.13.15) is an important enzyme, not only in the formation of bile acids from cholesterol intermediates in the liver but also in the removal of cholesterol by side chain hydroxylation in extrahepatic tissues. The enzyme has been assayed by complicated methods using radiolabel...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:10.1194/jlr.D200045-JLR200
更新日期:2003-12-01 00:00:00
abstract::Human apolipoprotein (apo) E occurs as three common isoforms (apoE4, E3, and E2), all of which influence plasma cholesterol levels. Although both apoE4 and E3 bind with equal effectiveness to the low density lipoprotein receptor, they associate preferentially with different classes of plasma lipoproteins: apoE4 with v...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1990-08-01 00:00:00
abstract::The genus Acinetobacter is composed of ubiquitous, generally nonpathogen environmental bacteria. Interest concerning these microorganisms has increased during the last 30 years, because some strains, belonging to the so-called A. baumannii-A. calcoaceticus complex, have been implicated in some severe pathological stat...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:10.1194/jlr.M600323-JLR200
更新日期:2007-05-01 00:00:00
abstract::Ceramides containing phytosphingosine as base and one of the fatty acids 16:0, 18:0, 20:0, 22:0, 23:0, and 24:0, were prepared by direct coupling in the presence of a mixed carbodiimide. The ceramides were analyzed as the 1,3,4-tri-O-trimethylsilyl ether derivatives by gas-liquid chromatography-mass spectrometry. Gas ...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1970-05-01 00:00:00
abstract::The characteristics of 7 alpha-dehydroxylase, a bile acid-biotransforming enzyme, were determined using dialyzed cell extracts of Eubacterium sp. V.P.I. 12708. 7 alpha-Dehydroxylase was induced by cholic acid in this organism. Induction by cholic acid resulted in the differential synthesis of at least five new polypep...
journal_title:Journal of lipid research
pub_type: 杂志文章
doi:
更新日期:1981-08-01 00:00:00