scholarly journals Binding of bile acids by 100 000g supernatants from rat liver

1977 ◽  
Vol 162 (3) ◽  
pp. 659-664 ◽  
Author(s):  
R C Strange ◽  
I A Nimmo ◽  
I W Percy-Robb
Keyword(s):  
Molecular Weight ◽  
Bile Acids ◽  
Rat Liver ◽  
Chenodeoxycholic Acid ◽  
Lithocholic Acid ◽  
Equilibrium Dialysis ◽  
Acid Transport ◽  
Binding Characteristics ◽  
Glycocholic Acid ◽  
Prominent Peak

1. The binding of glycocholic acid, chenodeoxycholic acid and lithocholic acid to rat liver 1000 000g supernatants was studied by equilibrium dialysis. 2. The binding characteristics of the bile acids suggest that the binding components are involved in bile acid transport. 3. When mixtures of [14C]lithocholic acid and liver supernatants were eluted from columns of Sephadex G-75, a prominent peak of [14C]lithocholic acid appeared with proteins of mol.wt. approx. 40000. A second, smaller, peak of [14C]lithocholic acid was eluted with proteins of mol.wt. approx. 100000. 4. The inclusion of cholic acid, glycocholic acid or chenodeoxycholic acid in the eluting buffer decreased the amount of [14C]lithocholic acid that was eluted with the higher-molecular-weight component.

scholarly journals Effects of clofibrate on some microsomal hydroxylations involved in the formation and metabolism of bile acids in rat liver

1976 ◽  
Vol 156 (2) ◽  
pp. 445-448 ◽  
Author(s):  
B O Angelin ◽  
I Björkhem ◽  
K Einarsson
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Rat Liver ◽  
Lithocholic Acid ◽  
Present Knowledge ◽  
Acid Formation ◽  
Microsomal Metabolism ◽  
Endogenous Cholesterol

1. The liver microsomal metabolism of [4-14C]cholesterol, endogenous cholesterol, 7 α-hydroxy-4-[6 β-3H]cholesten-3-one, 5-β-[7 β-3H]cholestane-3 α, 7 α-diol and [3H]lithocholic acid was studdied in control and clofibrate (ethyl p-chlorophenoxyisobutyrate)-treated rats. 2. The extent of 7 α-hydroxylation of exogenous [414C]cholesterol and endogenous cholesterol, the latter determined with a mass fragmentographic technique, was the same in the two groups of rats. The extent of 12 α-hydroxylation of 7 α-hydroxy-4-cholesten-3-one and 5 β-cholestane-3 α, 7 α-diol was increased by about 60 and 120% respectively by clofibrate treatment. The 26-hydroxylation of 5 β-cholestane-3 α, 7 α-diol was not significantly affected by clofibrate. The 6 β-hydroxylation of lithocholic acid was about 80% higher in the clofibrate-treated animals than in the controls. 3. The results are discussed in the context of present knowledge about the liver microsomal hydroxylating system and bile acid formation in patients with hypercholesterolaemia, treated with clofibrate.

Uptake of bile acids by perfused rat liver

1976 ◽  
Vol 231 (3) ◽  
pp. 734-742 ◽  
Author(s):  
J Reichen ◽  
G Paumgartner
Keyword(s):  
Bile Acids ◽  
Rat Liver ◽  
Chenodeoxycholic Acid ◽  
Competitive Inhibition ◽  
Compartment Model ◽  
Hepatic Uptake ◽  
Perfused Rat Liver ◽  
Multiple Indicator Dilution ◽  
Rapid Injection ◽  
Carrier Mediated Transport

The uptake of 14C-labeled cholic, taurocholic, and chenodeoxycholic acid by the perfused rat liver was studied to characterize the mechanism responsible for hepatic uptake of bile acids. A rapid-injection multiple indicator-dilution technique and the three-compartment model of Goresky were employed. The kinetics of hepatic uptake of the three bile acids could be described by the Michaelis-Menten equation. The maximal uptake velocities (Vmax) were 24.9 +/- 2.2 (mean +/- SD), 20.8 +/- 1.2, 1.2, and 11.4 +/- 0.9 nmol/s-g liver for cholic, taurocholic, and chenodeoxycholic acid, respectively. The corresponding apparent half-saturation constants (Km) were 526 +/- 125, 258 +/- 43, and 236 +/- 48 nmol/g liver. Competitive inhibition could be demonstrated between cholate and taurocholate as well as between cholate and chenodeoxycholate. Substitution of 94% of the Na+ in the perfusion medium decreased the Vmax and the apparent Km of taurocholate uptake by 68 and 55%, respectively. These findings are consistent with the hypothesis that bile acids are taken up into the hepatocyte by Na+-dependent carrier-mediated transport.

scholarly journals Properties of the canalicular bile acid transport system in rat liver

1987 ◽  
Vol 242 (2) ◽  
pp. 465-469 ◽  
Author(s):  
P J Meier ◽  
A S Meier-Abt ◽  
J L Boyer
Keyword(s):  
Bile Acid ◽  
Substrate Specificity ◽  
Bile Acids ◽  
Rat Liver ◽  
Transport System ◽  
Acid Transport ◽  
Bile Acid Transport ◽  
Canalicular Bile ◽  
Disulphonic Acid ◽  
Bile Acid Carrier

4,4-Di-isothiocyanostilbene-2,2′-disulphonic acid inhibition of taurocholate efflux from canalicular vesicles was used to demonstrate that potential driven and ‘carrier’-mediated canalicular excretion of taurocholate occur via a common, rather than two separate, pathways. This electrogenic canalicular bile acid ‘carrier ’ preferentially transports trihydroxylated and conjugated dihydroxylated bile acids, but not the unphysiological oxo bile acids, and possibly extends its substrate specificity to other amphipathic molecules such as sulphobromophthalein.

scholarly journals Distinct forms of cytochrome P-450 are responsible for 6β-hydroxylation of bile acids and of neutral steroids

1991 ◽  
Vol 275 (1) ◽  
pp. 105-111 ◽  
Author(s):  
P Zimniak ◽  
E J Holsztynska ◽  
A Radominska ◽  
M Iscan ◽  
R Lester ◽  
...  
Keyword(s):  
Bile Acids ◽  
Steroid Hormones ◽  
Rat Liver ◽  
Lithocholic Acid ◽  
Structural Elements ◽  
Differential Inhibition ◽  
Mutual Inhibition ◽  
Hydroxylation Reaction ◽  
Differential Responses ◽  
Cytochrome P 450

Cytochrome P-450-dependent 6 beta-hydroxylation of bile acids in rat liver contributes to the synthesis of the quantitatively important pool of 6-hydroxylated bile acids, as well as to the detoxification of hydrophobic bile acids. The lithocholic acid 6 beta-hydroxylation reaction was investigated and compared with androstenedione 6 beta-hydroxylation. Differential responses of these two activities to inducers and inhibitors of microsomal P-450 enzymes, lack of mutual inhibition by the two substrates and differential inhibition by antibodies raised against several purified hepatic cytochromes P-450 were observed. From these results it was concluded that 6 beta-hydroxylation of lithocholic acid is catalysed by P-450 form(s) different from the subfamily IIIA cytochromes P-450 which are responsible for the bulk of microsomal androstenedione 6 beta-hydroxylation. Similar, but more tentative, results revealed that the 7 alpha-hydroxylation of lithocholic acid and of androstenedione may be also catalysed by distinct P-450 enzymes. The results indicate that cytochromes P-450 hydroxylating bile acids are distinct from analogous enzymes that carry out reactions of the same regio- and stereo-specificity on neutral steroids (steroid hormones). A comparison of pairs of cytochromes P-450 that catalyse the same reaction on closely related steroid molecules will help to define those structural elements in the proteins that determine the recognition of their respective substrates.

scholarly journals Nuclear and cytosolic distribution of conjugated cholic acid and radiolabelled glycocholic acid in rat liver

1979 ◽  
Vol 178 (1) ◽  
pp. 71-78 ◽  
Author(s):  
R C Strange ◽  
G J Beckett ◽  
I W Percy-Robb
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Cholic Acid ◽  
Rat Liver ◽  
Superior Mesenteric Vein ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Acid Receptor ◽  
Glycocholic Acid ◽  
Bile Acid Receptor

1. Normally fed and cholestyramine-treated rats were injected through the superior mesenteric vein with different amounts of radiolabelled glycoholic acid and the appearance of radioactivity in bile was measured. 2. In normally fed rats radioactivity appeared in bile within 30 s of injection and reached a maximum after 2 1/2 min; in the cholestyramine-treated animals the appearance of radioactivity was slower and less of the injected material was excreted into bile. 3. At 10 min after injection, livers were removed and the amounts of radioactive glycoholic acid and endogenous cholic acid conjugates in nuclei and cytosol were determined; most of the bile acid was found in the cytosol, only small amounts being found in nuclei. 4. Nuclear preparations from both normally fed and cholestyramine-fed rats were extracted with KCl (0.4 M) in an attempt to identify a putative bile acid receptor, but no such receptor was found. 5. Regulation of bile acid synthesis does not involve nuclear binding of bile acids.

scholarly journals Effects of bile acids on human airway epithelial cells: implications for aerodigestive diseases

2017 ◽  
Vol 3 (1) ◽  
pp. 00107-2016 ◽  
Author(s):  
Adil Aldhahrani ◽  
Bernard Verdon ◽  
Chris Ward ◽  
Jeffery Pearson
Keyword(s):  
Cell Death ◽  
Epithelial Cell ◽  
Lung Disease ◽  
Bile Acids ◽  
Chenodeoxycholic Acid ◽  
Deoxycholic Acid ◽  
Lithocholic Acid ◽  
Bronchial Epithelial Cell ◽  
Epithelial Cell Line ◽  
Bronchial Epithelial

Gastro-oesophageal reflux and aspiration have been associated with chronic and end-stage lung disease and with allograft injury following lung transplantation. This raises the possibility that bile acids may cause lung injury by damaging airway epithelium. The aim of this study was to investigate the effect of bile acid challenge using the immortalised human bronchial epithelial cell line (BEAS-2B).The immortalised human bronchial epithelial cell line (BEAS-2B) was cultured. A 48-h challenge evaluated the effect of individual primary and secondary bile acids. Post-challenge concentrations of interleukin (IL)-8, IL-6 and granulocyte−macrophage colony-stimulating factor were measured using commercial ELISA kits. The viability of the BEAS-2B cells was measured using CellTiter-Blue and MTT assays.Lithocholic acid, deoxycholic acid, chenodeoxycholic acid and cholic acid were successfully used to stimulate cultured BEAS-2B cells at different concentrations. A concentration of lithocholic acid above 10 μmol·L−1 causes cell death, whereas deoxycholic acid, chenodeoxycholic acid and cholic acid above 30 μmol·L−1 was required for cell death. Challenge with bile acids at physiological levels also led to a significant increase in the release of IL-8 and IL6 from BEAS-2B.Aspiration of bile acids could potentially cause cell damage, cell death and inflammation in vivo. This is relevant to an integrated gastrointestinal and lung physiological paradigm of chronic lung disease, where reflux and aspiration are described in both chronic lung diseases and allograft injury.

scholarly journals A low-molecular-weight protein from rat liver that resembles ligandin in its binding properties

1976 ◽  
Vol 155 (3) ◽  
pp. 511-521 ◽  
Author(s):  
B Ketterer ◽  
E Tipping ◽  
J F Hackney ◽  
D Beale
Keyword(s):  
Molecular Weight ◽  
Rat Liver ◽  
Binding Characteristics ◽  
Wide Range ◽  
Isoelectric Points ◽  
Weight Protein ◽  
Low Molecular Weight Protein ◽  
Bile Acids And Salts ◽  
Peptide Maps ◽  
Three Components

A protein of S20,W 1.6S and mol.wt. 14000, which binds covalently a metabolite of the aminoazodye carcinogen NN-dimethyl-4-amino-3′-methylazobenzene, was isolated from rat liver cytosol from both carcinogen-treated and normal rats. The protein binds non-covalently palmitoyl-CoA, fatty acids, bilirubin, sex steroids and their sulphates, bile acids and salts, bromosulphophthalein, diethylstilboestrol and 20-methylcholanthrene with a wide range of affinities. The protein is isolated as three components with isoelectric points of 5.0, 5.9 and 7.6 by a method involving isoelectric focusing. All three components have closely similar amino acid analyses, tryptic-peptide ‘maps’ and u.v. spectra. Each single component redistributes into all three on further electrophoresis. However, the three forms differ in their binding characteristics, the form of pI 7.6 having much the highest affinity for compounds bound non-covalently. The protein was identified immunologically in rat liver, small intestine, adipose tissue, skeletal muscle, myocardium and testis. The protein was compared with other hepatic binding-protein preparations of similar molecular weight.

scholarly journals The synthesis of bile acids in perfused rat liver subjected to chronic biliary drainage

1970 ◽  
Vol 118 (3) ◽  
pp. 519-530 ◽  
Author(s):  
I. W. Percy-Robb ◽  
G. S. Boyd
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Cholic Acid ◽  
Rat Liver ◽  
Chenodeoxycholic Acid ◽  
Biliary Drainage ◽  
Specific Radioactivity ◽  
Mevalonic Acid ◽  
Liver Cholesterol ◽  
Microscopic Appearance

1. Isolated rat liver was perfused with heparinized whole blood under physiological pressure resulting in the secretion of bile at about the rate observed in vivo. 2. The preparation remained metabolically active for 4h and was apparently normal in function and microscopic appearance. 3. When the perfusate plasma and liver cholesterol pool was labelled by the introduction of [2-14C]mevalonic acid the specific radioactivity of the perfusate cholesterol increased. The biliary acids (cholic acid and chenodeoxycholic acid) were labelled and had the same specific radioactivity. 4. Livers removed from rats immediately after, and 40h after, the start of total biliary drainage, were perfused; increased excretion rates of both cholic acid and chenodeoxycholic acid were found when the liver donors had been subjected to biliary drainage. 5. The incorporation of [2-14C]mevalonic acid or rat lipoprotein labelled with [14C]cholesterol into bile acids was studied. 6. A dissociation between the mass of bile acid excreted and the rate of incorporation of 14C was found. This was attributed to the changing specific radioactivity of the cholesterol pool acting as the immediate bile acid precursor.

scholarly journals Formation of Lithocholic Acid from Chenodeoxycholic Acid in the Rat. Bile Acids and Steroids 103.

1960 ◽  
Vol 14 ◽  
pp. 1815-1818 ◽  
Author(s):  
Arne Norman ◽  
Jan Sjövall ◽  
Thor A. Bak ◽  
E. Varde ◽  
Gertrud Westin
Keyword(s):  
Bile Acids ◽  
Chenodeoxycholic Acid ◽  
Lithocholic Acid ◽  
Rat Bile
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