Abstract：
:Bile acids labeled with 3H on the sterol nucleus lose a substantial fraction of label during enterohepatic cycling and conversion to secondary bile acids. We tested the isotopic stability of a side-chain 3H label, [22,23-3H]cholic acid in humans. The 3H-labeled compound was administered simultaneously with [24-14C]cholic acid to four healthy volunteers. Duodenal bile was collected daily for 5 days after isotope administration to determine the ratio of 3H/14C in bile acids. Urine was collected to determine loss of radioactivity by this route. Cholic acid and deoxycholic acid were isolated from biliary bile acids by thin-layer chromatography after deconjugation with cholylglycine hydrolase. The ratio of 3H/14C in cholic acid and deoxycholic acid remained constant and identical to that of the administered mixture in all subjects, indicating stability of the 3H label during enterohepatic cycling. Cumulative loss of 3H in urine averaged only 1.2% of administered dose and was identical to loss of 14C (average 1.3%) indicating little if any transfer of 3H from bile acid to body water. Deconjugation of biliary bile acids by alkaline hydrolysis resulted in 15-20% loss of 3H label, consistent with known base-catalyzed exchange of alpha-carbon protons on carboxylic acids. We conclude that [22,23-3H]cholic acid is a biologically stable, and therefore reliable, isotopic tracer of cholic acid in humans during enterohepatic cycling including conversion to deoxycholic acid, provided deconjugation is performed enzymatically. Because the 22,23-3H label can be inserted into most C24 bile acids, it appears the best way to tag 3H-labeled bile acids for metabolic studies.
journal_name
J Lipid Resjournal_title
Journal of lipid researchauthors
Duane WC,Schteingart CD,Ton-Nu HT,Hofmann AFsubject
Has Abstractpub_date
1996-02-01 00:00:00pages
431-6issue
2eissn
0022-2275issn
1539-7262journal_volume
37pub_type
杂志文章abstract：:Membrane-bound proteins have been proposed to mediate the transport of long-chain FA (LCFA) transport through the plasma membrane (PM). These proposals are based largely on reports that PM transport of LCFAs can be blocked by a number of enzymes and purported inhibitors of LCFA transport. Here, using the ratiometric p...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.RA120000648
更新日期：2020-05-01 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：:Sonication of rat fat cells caused an increase in lipolysis in the absence of lipolytic stimulants (basal lipolysis) and loss of epinephrine responsiveness. Sonication of endogenous lipid droplets from fat cells also induced an increase in lipolysis in the presence of hormone-sensitive lipase (HSL) and loss of epineph...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1994-01-01 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：:Serum paraoxonase (PON1) is a HDL-associated enzyme exhibiting potentially antiatherogenic properties. Here, we examined the common PON1-192R/Q human polymorphism. Despite numerous studies, the effect of this polymorphism on the antiatherogenic potential of PON1 is yet unresolved. Our structural model suggests that am...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M600297-JLR200
更新日期：2006-11-01 00:00:00
abstract：:Lipoprotein lipase (LPL) hydrolyzes circulating lipoprotein triglyceride molecules while it is associated with the luminal surface of capillary endothelial cells. The precise molecular mechanism by which LPL attaches to these cells is unknown. LPL and a number of other molecules, including growth factors and clotting ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1993-11-01 00:00:00
abstract：:This report describes the chemical synthesis of isoursocholic acid (3 beta, 7 beta, 12 alpha-trihydroxy-5 beta-cholanoic acid) from its corresponding 3 alpha-analog. The method consists of refluxing a mixture of ursocholic acid, triphenylphosphine, and diethyl azodicarboxylate in benzene solution with an acid such as ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1991-08-01 00:00:00
abstract：:The oxidation of the side chain of 3 alpha, 7 alpha-dihydroxy-5 beta-cholestanoic acid (DHCA) into chenodeoxycholic acid has been studied in subcellular fractions of rat liver. The product was separated from the substrate by high pressure liquid chromatography and identified by gas-liquid chromatography-mass spectrome...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1986-06-01 00:00:00
abstract：:In mammals, the esterification of sterols by ACAT plays a critical role in eukaryotic lipid homeostasis. Using the predominant isoform of the yeast ACAT-related enzyme family, Are2p, as a model, we targeted phylogenetically conserved sequences for mutagenesis in order to identify functionally important motifs. Deletio...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：2001-08-01 00:00:00
abstract：:Changes in the cellularity of various adipose tissues in growing cattle were analyzed. Fifty male cattle were slaughtered between 15 and 65% of mature weight. The whole adipose mass, separated by dissection, was divided into three parts: subcutaneous, intermuscular, and internal adipose tissues. Lipid content, cell si...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1981-03-01 00:00:00
abstract：:This review presents an overview of mammalian phospholipid synthesis and the cellular locations of the biochemical activities that produce membrane lipid molecular species. The generalized endoplasmic reticulum compartment is a central site for membrane lipid biogenesis, and examples of the emerging relationships betw...
journal_title：Journal of lipid research
pub_type： 杂志文章,评审
doi：10.1194/jlr.R800049-JLR200
更新日期：2009-04-01 00:00:00
abstract：:Human striated muscle samples, from male control and Duchenne muscular dystrophy-affected children, were subjected to cluster-time-of-flight secondary ion mass spectrometry (cluster-ToF-SIMS) imaging using a 25 keV Bi(3)(+) liquid metal ion gun under static SIMS conditions. Spectra and ion density maps, or secondary i...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M700421-JLR200
更新日期：2008-02-01 00:00:00
abstract：:The mRNA level for cytosolic NADP-dependent isocitrate dehydrogenase (IDH1) increases 2.3-fold, and enzyme activity of NADP-isocitrate dehydrogenase (IDH) 63%, in sterol-deprived HepG2 cells. The mRNA levels of the NADP- and NAD-dependent mitochondrial enzymes show limited or lack of regulation under the same conditio...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M300285-JLR200
更新日期：2003-11-01 00:00:00
abstract：:Lipids are used as cellular building blocks and condensed energy stores and also act as signaling molecules. The glycerolipid/ fatty acid cycle, encompassing lipolysis and lipogenesis, generates many lipid signals. Reliable procedures are not available for measuring activities of several lipolytic enzymes for the purp...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.D058438
更新日期：2016-01-01 00:00:00
abstract：:For the last 30 years fibrates have been widely prescribed to treat human dyslipidemia. However, the primary mechanism by which they lower plasma lipid levels is still unknown. Studies with transgenic mice have suggested that changes in apoC-III expression levels have a dramatic influence on plasma triglyceride levels...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1995-12-01 00:00:00
abstract：:Skeletal muscle has two circulatory routes, nutritive (in contact with muscle) and non-nutritive (part of which is located in the connective tissue), and the balance of flow between the two is controlled by neural input and circulating vasomodulators. The purpose of this study was to assess muscle triglyceride hydroly...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：2000-03-01 00:00:00
abstract：:Fatty acid translocase (FAT/CD36) is a membrane protein putatively involved in the transmembrane transport of long-chain fatty acids. We tested the hypothesis that expression of this protein in H9c2, a rat heart cell line normally not expressing FAT, would increase cellular palmitate uptake. We were able to stably tra...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1998-10-01 00:00:00
abstract：:Using the "ghost method" previously applied to study the binding of palmitate to bovine serum albumin (BSA) (Bojesen, I. N., and E. Bojesen. 1992. J. Lipid Res. 33: 1327-1334) we have measured the water-phase concentrations of arachidonate (AR) and oleate (OL) in 165 mM KCl and in 165 mM NaCl, 2 mM phosphate buffer at...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1994-05-01 00:00:00
abstract：:Neuroinflammation, caused by 6 days of intracerebroventricular infusion of a low dose of lipopolysaccharide (LPS; 0.5 ng/h), stimulates brain arachidonic acid (AA) metabolism in rats, but 6 weeks of lithium pretreatment reduces this effect. To further understand this action of lithium, we measured concentrations of ei...
journal_title：Journal of lipid research
pub_type： 杂志文章,收录出版
doi：10.1194/jlr.M002469
更新日期：2010-05-01 00:00:00
abstract：:Several recent reports have examined whether there is a correlation between the presence of some minor alleles of the highly polymorphic apolipoprotein B gene and atherosclerosis and premature heart disease. The present study extends this investigation. A high-resolution method was used to study the allele frequencies...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1990-04-01 00:00:00
abstract：:The objective of this study was to investigate the mobilization of individual fatty acids from human subcutaneous adipose tissue in vivo. Concentrations of individual non-esterified fatty acids were measured in arterialized plasma and in the venous drainage from subcutaneous abdominal adipose tissue in eight normal su...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1996-09-01 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：:The secondary bile acid lithocholic acid (LCA) and its derivatives act as selective modulators of the vitamin D receptor (VDR), although their structures fundamentally differ from that of the natural hormone 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3)]. Here, we have determined the crystal structures of the ligand-binding...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M038307
更新日期：2013-08-01 00:00:00
abstract：:High plasma cholesterol levels are found in several metabolic disorders and their reductions are advocated to reduce the risk of atherosclerosis. A way to lower plasma lipids is to curtail lipoprotein production; however, this is associated with steatosis. We previously showed that microRNA (miR)-30c lowers diet-induc...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M081299
更新日期：2018-01-01 00:00:00
abstract：:Elongation of very long chain fatty acids (ELOVL)5 is one of seven mammalian fatty acid condensing enzymes involved in microsomal fatty acid elongation. To determine the in vivo substrates and function of ELOVL5, we generated Elovl5(-/-) mice. Studies using liver microsomal protein from wild-type and knockout mice dem...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M800383-JLR200
更新日期：2009-03-01 00:00:00
abstract：:Delta-6 desaturase (D6D) catalyzes the first step in the synthesis of highly unsaturated fatty acids (HUFA) such as arachidonic (AA), docosapentaenoic (DPAn-6), and docosahexaenoic (DHA) acids, as well as the last desaturation of DPAn-6 and DHA. We created D6D-null mice (-/-), which enabled us to study HUFA deficiency...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M900039-JLR200
更新日期：2009-09-01 00:00:00
abstract：:The enzymic incorporation of choline-1,2-(14)C from CDP-choline-1,2-(14)C into phosphatidylcholine by spinach leaf preparations was characterized. The enzyme catalyzing the incorporation, choline phosphotransferase, had a pH optimum of about 8.0 and required either Mn(2+) or Mg(2+) as cofactor. The saturation concentr...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1971-07-01 00:00:00
abstract：:The rate-limiting step in the transit of dietary fat across the intestinal absorptive cell is its exit from the endoplasmic reticulum (ER) in a specialized ER-to-Golgi transport vesicle, the prechylomicron transport vesicle (PCTV). PCTV bud off from the ER membranes and have unique features; they are the largest ER-de...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M002758
更新日期：2010-05-01 00:00:00
abstract：:Adipocyte differentiation and function have become areas of intense focus in the field of energy metabolism; however, understanding the role of specific genes in the establishment and maintenance of fat cell function can be challenging and complex. In this review, we offer practical guidelines for the study of adipocy...
journal_title：Journal of lipid research
pub_type： 杂志文章,评审
doi：10.1194/jlr.R046441
更新日期：2014-04-01 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
