Abstract：
:Two assays for the quantitative measurement of HMG-CoA reductase, the major regulatory enzyme in hepatic cholesterol biosynthesis, are described. The first of these procedures employs thin-layer chromatography (TLC) of the reaction product on plastic-backed silica gel G strips impregnated with ammonium carbonate. The TLC strip is then cut into 14 segments and each segment is assayed for radioactivity. Extraction efficiency and exact chromatographic mobility are monitored by the use of authentic [4-(3)H]mevalonolactone as an internal reference. A wide and complete separation is achieved between HMG and mevalonolactone. Also the radiochemical purity of biosynthetic [3-(14)C]mevalonolactone can be assessed by measurement of the (3)H/(14)C ratio across the mevalonolactone peak. While the TLC assay is accurate and sensitive, it is laborious. Therefore a second assay procedure was developed using chloroform extraction of an incubation mixture saturated with solid equal molar KH(2)PO(4)-K(2)HPO(4) at pH 6.8. Extraction efficiency was monitored by the addition of authentic [4-(3)H]mevalonolactone as an internal reference. The chloroform assay procedure was compared with the TLC procedure over a wide range of enzyme activities, both for rat liver microsomal HMG-CoA reductase and for solubilized enzyme. Excellent correspondence (r = 0.999) between the two assays was observed. TLC performed on the chloroform extract demonstrated that biosynthetic [3-(14)C]mevalonolactone was the only (14)C-labeled compound present in the extract. The chloroform extraction assay is rapid; 20-30 samples can be processed in 2-3 hr. This procedure should facilitate studies concerning the nature and regulation of HMG-CoA reductase.
journal_name
J Lipid Resjournal_title
Journal of lipid researchauthors
Ackerman ME,Redd WL,Tormanen CD,Hardgrave JE,Scallen TJsubject
Has Abstractpub_date
1977-05-01 00:00:00pages
408-13issue
3eissn
0022-2275issn
1539-7262journal_volume
18pub_type
杂志文章abstract：:A variety of methods are currently used to analyze HL and LPL activities in mice. In search of a simple methodology, we analyzed mouse preheparin and postheparin plasma LPL and HL activities using specific polyclonal antibodies raised in rabbit against rat HL (anti-HL) and in goat against rat LPL (anti-LPL). As an alt...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.D700021-JLR200
更新日期：2007-12-01 00:00:00
abstract：:An improved method for the synthesis of phosphatidylcholines from phosphatidic acid and choline is described. The technique utilizes the tetraphenylborate salt of choline together with the condensing agent 2,4,6-triisopropylbenzenesulfonyl chloride. The yields in the reaction are consistently in the range 70-75%. ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1984-10-01 00:00:00
abstract：:Supersaturation and rapid nucleation of cholesterol in bile are of key importance in the pathogenesis of cholesterol gallstones. While the effects of bile acids and phospholipids on cholesterol saturation of bile have been extensively studied, their influence on the cholesterol nucleation time has not been compared. W...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1993-09-01 00:00:00
abstract：:Niemann-Pick disease, type C (NP-C), often associated with Niemann-Pick disease, type C1 (NPC1) mutations, is a cholesterol-storage disorder characterized by cellular lipid accumulation, neurodegeneration, and reduced steroid production. To study NPC1 function in vivo, we cloned zebrafish npc1 and analyzed its gene ex...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M012377
更新日期：2011-07-01 00:00:00
abstract：:The potential role of the very low density lipoprotein (VLDL) receptor in mediating VLDL-induced plasminogen activator inhibitor-1 (PAI-1) expression was studied in vitro. Cultured endothelial cells incubated with VLDL showed an increased secretion of PAI-1. This response to VLDL could be completely prevented by the r...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1999-05-01 00:00:00
abstract：:The effect of fat feeding on adipocyte insulin binding was examined to expand a study of adaptive changes in plasma membrane functions. Cells from rats fed a high fat (L) diet for five to seven days bound less insulin and showed a decreased response to insulin (glucose oxidation) compared to those from rats fed a high...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1976-11-01 00:00:00
abstract：:After crossing floxed stearoyl-CoA desaturase-1 (Scd1fl/fl) mice with LDL receptor-null (ldlr-/-) mice, and then Villin Cre (VilCre) mice, enterocyte Scd1 expression in Scd1fl/fl/ldlr-/-/VilCre mice was reduced 70%. On Western diet (WD), Scd1fl/fl/ldlr-/- mice gained more weight than Scd1fl/fl/ldlr-/-/VilCre mice (P <...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M083527
更新日期：2018-10-01 00:00:00
abstract：:The measurement of apolipoprotein B (apoB) in purified lipoproteins by immunological assays is subject to criticism because of denatured epitopes or immunoreactivity differences between purified lipoproteins and standard. Chemical methods have therefore been developed, such as the selective precipitation of apoB follo...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：2000-07-01 00:00:00
abstract：:Percent cholesterol absorption was measured in 94 normal subjects aged 17- 80 years while consuming diets generally low in cholesterol (mean intake = 226 +/- 126 mg/day). A new dual stable isotope method was used where a cholesterol tracer containing 6 extra mass units was given intravenously and another tracer with 5...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1999-02-01 00:00:00
abstract：:A gas-liquid chromatography-flame ionization detection method is described for measuring plasma levels of eicosatetraynoic acid using eicosatriynoic acid as an internal standard. The technique is simple, rapid, and reproducible. Eicosatetraynoic acid and eicosatriynoic acid behave similarly in the extraction system ch...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1981-03-01 00:00:00
abstract：:HDL-associated paraoxonase type 1 (PON1) can protect LDL and HDL against oxidative modification in vitro and therefore may protect against cardiovascular disease. We investigated the effects of PON1 levels, activity, and genetic variation on high density lipoprotein-cholesterol (HDL-C) levels, circulating oxidized LDL...
journal_title：Journal of lipid research
pub_type： 临床试验,杂志文章,随机对照试验
doi：10.1194/jlr.M400052-JLR200
更新日期：2005-03-01 00:00:00
abstract：:N-acylethanolamines (NAEs) are a group of lipid mediators synthesized in response to a number of physiological and pathological stimuli. Because of the low tissue concentrations of NAEs, analyses often include liquid extraction followed by solid-phase extraction and subsequent quantitation by LC/MS or GC/MS. Reported ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.D004606
更新日期：2010-10-01 00:00:00
abstract：:Semi-purified diets supplemented with either a high linoleate (n-6) (safflower) oil or a high alpha-linolenate (n-3) (perilla) oil were fed to mouse mothers and their offspring through 6 weeks of age. The proportions of n-3 and n-6 highly unsaturated fatty acids in brain phospholipids reflected the n-3/n-6 balance of ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1993-02-01 00:00:00
abstract：:Triacylglycerols (TG) are the major storage form of energy in eukaryotic organisms and are synthesized primarily by acyl CoA:1,2-diacylglycerol acyltransferase (DGAT) enzymes. In vitro DGAT activity has previously been quantified by measuring the incorporation of either radiolabeled fatty acyl CoA or diacylglycerol (D...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.D016626
更新日期：2011-09-01 00:00:00
abstract：:Rat liver microsomes were incubated with the monofunctional aminoreagent fluorescamine. Although the probe easily penetrated the membranes, two pools of phosphatidylethanolamine (PE) could be detected. The first pool rapidly reacted with the probe and comprised 80% of the total PE. The second pool exhibited a very slo...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1986-07-01 00:00:00
abstract：:Leukotrienes (LTs) play major roles in lung immune responses, and LTD4 is the most potent agonist for cysteinyl LT1, leading to bronchoconstriction and tissue remodeling. Here, we studied LT crosstalk between myeloid cells and pulmonary epithelial cells. Monocytic cells (Mono Mac 6 cell line, primary dendritic cells) ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M066910
更新日期：2016-09-01 00:00:00
abstract：:Human lysosomal acid lipase/cholesteryl ester hydrolase (hLAL) is essential for the intralysosomal metabolism of cholesteryl esters and triglycerides taken up by receptor-mediated endocytosis of lipoprotein particles. The key role of the enzyme in intracellular lipid homeostasis is illustrated by two lysosomal storage...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1999-02-01 00:00:00
abstract：:Palmitoleic acid is a minor monounsaturated fatty acid in the human diet and in blood plasma. Because macadamia oil is at least one potentially large source of palmitoleic acid, we tested its effect on plasma lipid levels against two other dietary fatty acids, oleic acid and palmitic acid. The dietary adjustments, thr...
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：:Biosynthesis of 5,15-dihydroxyeicosatetraenoic acid (5,15-diHETE) in leukocytes involves consecutive oxygenation of arachidonic acid by 5-lipoxygenase (LOX) and 15-LOX in either order. Here, we analyzed the contribution of cyclooxygenase (COX)-2 to the biosynthesis of 5,15-diHETE and 5,11-diHETE in isolated human leuk...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M017822
更新日期：2012-01-01 00:00:00
abstract：:Chronic inflammation contributes to cardiovascular disease. Increased levels of the inflammatory cytokine, TNF-α, are often present in conditions associated with cardiovascular disease risk, and TNF-α induces a number of pro-atherogenic effects in macrovascular endothelial cells, including expression of adhesion molec...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.RA119000256
更新日期：2020-01-01 00:00:00
abstract：:HDL and its major component, apolipoprotein A-I (apoA-I), play a central role in reverse cholesterol transport. We recently reported the involvement of a glycosylphosphatidylinositol anchor (GPI anchor) in the binding of HDL and apoA-I on human macrophages, and purified an 80 kDa HDL/apoA-I binding protein. In the pre...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M500425-JLR200
更新日期：2006-01-01 00:00:00
abstract：:A rapid and accurate method is described for the assay of cholesterol ester hydrolase (CEH) activity. Aliquots of the enzyme-substrate incubation mixture are extracted into isopropanol. The free cholesterol concentration in each extract is determined enzymatically using a single aqueous reagent containing cholesterol ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1978-09-01 00:00:00
abstract：:Incubation of low density lipoprotein (LDL) with endothelial cells converts it to a form that is avidly degraded by macrophages via the acetyl LDL receptor. This modification has previously been shown to be accompanied by extensive breakdown of the major LDL protein (apoB-100) to smaller peptides. ApoB-100 is known to...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1987-12-01 00:00:00
abstract：:Sulfoquinovosyl diglyceride from plant tissues is recovered in sizeable quantities, free from phospholipids and galactolipids. ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1966-07-01 00:00:00
abstract：:Cellular cholesterol is known to be under homeostatic control in nonsteroidogenic cells, and this intrigued us to understand how such control works in steroidogenic cells that additionally use cholesterol for steroid hormone synthesis. We employed primary culture of rat ovarian granulosa cells to study how steroidogen...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M030239
更新日期：2013-02-01 00:00:00
abstract：:The hepatic uptake of intravenously injected beta-very low density lipoprotein (beta-VLDL) in rabbits fed 2% (w/w) cholesterol for 3 weeks was investigated. In vitro studies were also conducted to examine the specificity and the capacity of the uptake in isolated liver parenchymal cells. The hepatic uptake of beta-VLD...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1993-04-01 00:00:00
abstract：:It was postulated that specialized microdomains of the plasma membrane, consistent with caveolae, might play a role in cholesterol trafficking in intestinal cells. The existence, therefore, of caveolin and the role of detergent-resistant microdomains of the plasma membrane in cholesterol trafficking were investigated ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1998-10-01 00:00:00
abstract：:We have developed a procedure to quantify apolipoprotein (apo) B-100, apoB-48, and apoE in human triglyceride-rich lipoproteins. This procedure permits delipidation of small amounts of triglyceride-rich lipoproteins without appreciable losses, and quantification of these apolipoproteins in samples containing as little...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1995-04-01 00:00:00
abstract：:HDL subspecies Lp(A-I) and Lp(A-I,A-II) have different anti-atherogenic potentials. To determine the role of lipoprotein lipase (LPL) and hepatic lipase (HL) in regulating these particles, we measured these enzyme activities in 28 healthy subjects with well-controlled Type 1 diabetes, and studied their relationship wi...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M300091-JLR200
更新日期：2003-08-01 00:00:00
abstract：:Apolipoprotein A-IV (apoA-IV) is involved in the metabolism of chylomicrons and high density lipoproteins. It displays genetic polymorphism due to two co-dominant alleles apoA-IV1 and apoA-IV2. The mutation that causes the polymorphism is a G to T substitution in the third base of codon 360 in the apoA-IV2 allele whic...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1991-03-01 00:00:00
