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PubMed1977

Enzymatic sulfation of bile salts. Partial purification and characterization of an enzyme from rat liver that catalyzes the sulfation of bile salts.

An enzyme system which catalyzes the transfer of sulfate group from 3'-phosphoadenosine-5'-phosphosulfate to bile salts has been identified and characterized from rat liver. The enzyme is present in the cytosol fraction of liver cells. The apparent Km value for 3'-phosphoadenosine-5'-phosphosulfate was 8 - 10(-6) M andhat for taurolithocholate was 5 - 10(-5) M. Sulfation occurred with conjugated as well as unconjugated bile salts, however, the rate of sulfation was higher with conjugated than unconjugated. The enzyme was present in rat liver and kidney, but not detectable in brain, lung, heart, spleen or intestinal mucosa. The activity is completely inhibited by p-chloromercuribenzoate indicating the enzyme requires a sulfhydryl group for activity. A molecular weight of 130 000 was estimated by gel-filtration technique and the enzyme shows an isoelectric point of 5.3.

Animals↗
PubMed1979

The preparation of 125I-labelled bile acid ligands for use in the radioimmunoassay of bile acids.

A general method for the preparation of 125I-labelled bile acid-histamine or 125I-labelled bile acid-tyramine conjugates is presented. The method is simple, quick and produces ligands in good yield (30%). The characteristics of a radioimmunoassay for conjugated chenodeoxycholic acid, based on an 125I-labelled ligand prepared by the method, are also described. The assay produced values for fasting serum concentrations of conjugated chenodeoxycholic acid that agree well with previous data.

Bile Acids and Salts↗
PubMed1987

Internal standards for quantitative gas chromatography of individual bile acids after group separation of bile acids in urine.

Sodium glyco-7 alpha,12 alpha-dihydroxy-5 beta-cholan-24-oate, sodium tauro-7 beta,12 beta-dihydroxy-5 beta-cholan-24-oate and disodium glyco-7 alpha,12 alpha-dihydroxy-5 beta-cholan-24-oate 7 alpha-sulphate have been synthesized for the first time. These compounds, together with 7 beta,12 beta-dihydroxy-5 beta-cholan-24-oic acid, which were added to a sample prior to extraction, were found to be useful as internal standards for determination by gas chromatography of individual bile acids in each fraction after group separation of urinary bile acids.

Bile Acids and Salts↗
PubMed1985

Bile acids. LXXVI. Analyses of bile acids and sterols by high-performance liquid chromatography with a microbore column.

The mobilities of several free and conjugated 5 beta-bile acids, cholesterol and analogues, and alpha, beta-unsaturated sterols and steroidal acids have been investigated with a microbore reversed-phase high-performance liquid chromatographic column (50 cm X 1 mm I.D., 12% C18) with appropriate solvent mixtures at flow-rates of 50-100 microliter/min and a UV monitor set at 193, 198, 212, or 243 nm. With a solvent mixture of 2-propanol-10 mM phosphate buffer, pH 7.0 (160:340) bile acids or their conjugates were separated in a manner similar to those by microBondapak columns (10% C18). The lower detection limit of the conjugates was 20 pmoles with the UV detector set at 193 nm, whereas the lower limit for alpha, beta-unsaturated keto sterols or steroidal acids was 5 pmoles at 243 nm. The detection limit for cholesterol with the UV monitor at 198 nm was 10 pmoles. Contributions of substituent groups of sterols to their time of elution (capacity factor) were calculated for several substituted 4-cholesten-3-ones.

Bile Acids and Salts↗
PubMed1977

Sterol and bile acid metabolism during development: 2. Identification of 3beta-hydroxy-5-cholenoic acid (an intermediate in alternate pathway of bile acid synthesis) in newborn and fetal guinea pig.

3beta-hydroxy-5-cholenoic acid was found in the bile and feces of newborn and fetal guinea pigs. The identity of this compound was confirmed by gas chromatography and mass spectrometry. This finding suggests that the formation of chenodeoxycholic acid through 3beta-hydroxy-5-cholenoic acid is intermediate in the early life of guinea pigs. Thus, it provides a useful model for studying the details of regulatory factors and significance of this pathway. This study also revealed that, unlike the adult guinea pig, the newborn guinea pig has significant amounts of glycine conjugates of bile acid.

Animals↗
PubMedDate not supplied

Influence of charge and steric bulk in the C-24 region on the interaction of bile acids with human apical sodium-dependent bile acid transporter.

The human apical sodium-dependent bile acid transporter (hASBT) is a potential target for drug delivery, but an understanding of hASBT substrate requirements is limited. The objective of this study was to evaluate the influence of ionic character and steric bulk in the C-24 region of bile acid conjugates in governing interaction with hASBT. Ionic character was studied using chenodeoxycholate (CDCA) conjugates of glutamic acid and lysine, which varied in charge (monoanionic, dianionic, cationic, neutral, and zwitterionic) and location of charge (proximal or distal to C-24). Steric effects were evaluated using ester conjugates that varied in ester substituent size (methyl, benzyl, and tert-butyl) and location (proximal and/or distal). Conjugate interaction with hASBT was assessed via transport and inhibition studies, using a hASBT-MDCK monolayer. Monoanionic, cationic, and neutral conjugates of CDCA exhibited high inhibitory potency (Ki<10 microM). High inhibition potency of neutral and cationic conjugates indicated that a negative charge is not essential for hASBT binding. Dianionic conjugates exhibited low inhibition potency (Ki>100 microM). Conjugates with a single bulky ester substituent proximal or distal to the C-24 region exhibited high inhibition potency. However, two bulky substituents practically abolished interaction. In transport studies, monoanionic conjugates were high affinity hASBT substrates. Meanwhile, cationic and zwitterionic conjugates were not substrates for hASBT. Overall, C-24 ionic character influenced interaction with hASBT. Although the presence of a single negative charge was not essential for interaction with hASBT, monoanionic conjugates were favored for hASBT-mediated transport compared to cationic and zwitterionic conjugates.

Bile Acids and Salts↗
PubMed1966

Comparative studies of bile salts, myxinol disulphate, the principal bile salt of hagfish (Myxinidae).

1. The principal bile salt, myxinol disulphate, of two hagfish species, Eptatretus stoutii and Myxine glutinosa, has been shown by chemical methods and by optical-rotatory and mass-spectral considerations to be probably the C-3,27-disulphate ester of 3beta,7alpha,16alpha,27-tetrahydroxy-5beta-cholestane. 2. Myxine liver sterols were about half ;free' and half esterified: cholesterol only was identified. 3. The chemical nature of myxinol is what might be expected for the bile alcohol of a very primitive vertebrate.

Animals↗
PubMed1970

Bilirubin conjugates of human bile. Isolation of phenylazo derivatives of bile bilirubin.

A method is presented that allows the isolation of eight different phenylazo derivatives of bile bilirubin. In step I of the isolation procedure, three bilirubin fractions (bilirubin fractions 1, 2 and 3) from human hepatic bile are separated by reverse-phase partition chromatography on silicone-treated Celite with the use of a solvent system prepared from butan-1-ol and 5mm-phosphate buffer, pH6.0. Azo coupling is then performed with diazotized aniline. The three azo pigment mixtures are subjected to step II, in which the above chromatography system is used again. With each azo pigment mixture this step brings about the separation of a non-polar and a polar azo pigment fraction (azo 1A and azo 1B, azo 2A and azo 2B, and azo 3A and azo 3B from bilirubin fractions 1, 2 and 3 respectively). Approximately equal amounts of non-polar and polar pigments are obtained from bilirubin fractions 1 and 2, whereas bilirubin fraction 3 yields azo 3B almost exclusively. In step IIIA the non-polar azo pigment fractions are fractionated further by adsorption chromatography on anhydrous sodium sulphate with the use of chloroform followed by a gradient of ethyl acetate in chloroform. Three azo pigments are thus obtained from both azo 2A (azo 2A(1), azo 2A(2) and azo 2A(3)) and azo 3A (azo 3A(1), azo 3A(2) and azo 3A(3)). The 2A pigments occur in approximately the following proportions: azo 2A(1), 90%; azo 2A(2), 10%; azo 2A(3), traces. The pigments are purified by crystallization, except for the A(3) pigments, which are probably degradation products arising from the corresponding A(2) pigments. In step IIIB the polar azo pigment fractions are subjected to reverse-phase partition chromatography on silicone-treated Celite with the use of a solvent system prepared from octan-1-ol-di-isopropyl ether-ethyl acetate-methanol-0.2m-acetic acid (1:2:2:3:4, by vol.). Azo pigment fractions 2B and 3B each yield six azo pigments (azo 2B(1) to azo 2B(6) and azo 3B(1) to azo 3B(6) respectively) together with small amounts of products of hydrolysis (azo 2A(B) and azo 3A(B)). Only one azo B pigment is obtained from bilirubin fraction 1, and this azo pigment is probably of the B(2) type. The yields of the azo 3B pigments suggest that these pigments are present in approximately the following proportions: azo 3B(1), 0-0.4%; azo 3B(2), traces; azo 3B(3), traces; azo 3B(4), 10%; azo 3B(5), 50%; azo 3B(6), 40%. Azo pigments 2B(1) to 2B(6) are estimated to occur in similar proportions. Since pairs of correspondingly numbered azo pigments from bilirubin fractions 1, 2 and 3 do not separate on rechromatography together (e.g. azo 2A(1) co-chromatographs with azo 3A(1), and azo 2B(6) co-chromatographs with azo 3B(6)), it is concluded that such pigments are chemically identical. The structures of the isolated phenylazo derivatives are discussed in an accompanying paper (Kuenzle 1970c).

Acetates↗
PubMed1972

Comparative studies of bile salts. A new type of bile salt from Arapaima gigas (Cuvier) (family Osteoglossidae).

1. Arapaima gigas bile salts were hydrolysed by alkali or cleaved with dioxan-trichloroacetic acid to give cholic acid, arapaimic acid, arapaimol-A and arapaimol-B. 2. I.r., n.m.r. and mass spectroscopy and [alpha](D) measurements indicated that arapaimic acid and arapaimol-A and -B are respectively 2alpha,3alpha,7alpha,12alpha-tetrahydroxy-5beta,25in-cholestan-26-oic acid, 5beta,25R-cholestane-2beta,3alpha,7alpha,12alpha,26-pentol and 5beta-cholestane-2beta,3alpha,7alpha,12alpha,26,27-hexol. 3. Partial synthesis of 2beta,3alpha,7alpha,12alpha-tetrahydroxy-5alpha- and -5beta-cholan-24-oic acid and their spectral examination fully confirmed these conclusions. 4. A. gigas bile salts show primitive features in that they comprise alcohol sulphates and a C(27) acid; they are also specialized in showing 2beta-hydroxylation.

Animals↗
PubMed2002

Bile acids regulate the ontogenic expression of ileal bile acid binding protein in the rat via the farnesoid X receptor.

BACKGROUND & AIMS: In the rat, an increase in ileal bile acid binding protein (IBABP) expression occurs during the third postnatal week. In vitro studies suggest that bile acids (BAs) increase IBABP transcription by activating the BA receptor, farnesoid X receptor (FXR). Thus, we investigated the role of BAs on the ontogenic expression of IBABP and whether FXR may mediate these effects. METHODS: Suckling rats were gavage-fed taurocholate for 3 days or were allowed to develop normally. Ileums were collected for Northern and Western blot analyses. Electrophoretic mobility shift assays for functional FXR were performed using nuclear extracts from ileums of both adult and developing rats. RESULTS: Taurocholate gavage significantly elevated IBABP messenger RNA and protein levels in suckling animals. Gelshift assays using adult ileal nuclear extracts incubated with a radiolabeled consensus inverted repeat-1 oligonucleotide (response element for FXR) revealed a high-molecular weight DNA/protein complex. Cold competition and supershift assays showed that this complex is sequence specific and confirmed that FXR is a component of the complex. Gelshift assays with nuclear extracts from rat ileum at different ages revealed absence of the DNA/protein complex in the second postnatal week when there is lack of IBABP expression and presence of these complexes at later ages when there is normally high expression. Western blot analyses showed FXR and its heterodimer partner, retinoid X receptor alpha, protein levels are low in the ileum during the suckling period and increase during the third postnatal week. CONCLUSIONS: BAs play a role in the normal developmental expression of IBABP through FXR activation, and decreased functional FXR in ileal nuclei during the suckling period may account, in part, for the lack of IBABP expression at this time.

Animals↗
PubMed1988

[Bile duct epithelium and bile duct atresia].

In order to investigate pathogenetic theories about the origins of biliary atresia, a model consisting of cell cultures of bile duct epithelium from the extrahepatic ducts of human and bovine origin is presented. The epithelial nature of the cultivated cells was documented by phase contrast microscopy, by electron microscopy and immunohistochemistry (anti-keratin). Inoculation studies of primary human cell cultures showed a cytopathic effect by light microscopy for all tested viruses (adeno, polio, herpes, rubella) except for reovirus type 3, for which a CPE was not demonstrable. A growth stimulating substrate for bile duct epithelial cells is described; among the purified growth factors epidermal growth factor was without effect (EGF), while cholecystokinin (CCK) led to an increase in cell numbers.

Animals↗
PubMed1979

Common bile duct and Oddi sphincter pressure before and after endoscopic papillotomy in patients with common bile duct stones.

Pressures in the Oddi sphincter and common bile duct were determined before, immediately after and several weeks after endoscopic papillotomy. Fifteen patients were included in the study. Significant decreases in Oddi sphincter and common bile duct pressures were found and the decrease in Oddi sphincter pressure was to some extent dependent upon the length of the papillotomy.

Adult↗
PubMedDate not supplied

Bile salt roles in bile-salt-stimulated lipase activity.

The hydrolysis of 4-nitrophenylacetate and phenylsalicylate, catalyzed by human milk lipase in the presence of a range of concentrations of sodium cholate, has been measured at pH 7.3 and 37.5 degrees C, and maximum activity was observed for both substrates at 1 mmole/dm-3 bile salt. Lineweaver-Burk plots for the enzyme-catalyzed hydrolysis of N-methylindoxyl myristate and 4-nitrophenyloctanoate yielded values of Km equal to 34 and 20 mumoles/dm-3, respectively. However, an increase in the concentration of the latter substrate beyond 10 mumoles/dm-3 was not accompanied by a corresponding increase in the rate of hydrolysis. Comparison of these hydrolysis data with literature data for a variety of hydrophobic substrates suggests that there are two roles for the bile salt in the enzyme-catalyzed reaction--the first involving binding onto several sites on the enzyme, and the second solubilization of oil-phase substrates.

Bile Acids and Salts↗
PubMed2007

Intrahepatic cystic lesions after hepatic portoenterostomy for biliary atresia with bile lake and dilated bile ducts.

BACKGROUND: Intrahepatic cystic lesions develop after hepatic portoenterostomy in some patients with biliary atresia and have been regarded as an indication of poor prognosis; however, there is confusion about the terminology and concepts of the lesions. We investigated whether the cystic lesions constituted a single entity. PATIENTS AND METHODS: From 1980 to 2005, we encountered 80 patients with biliary atresia. Abdominal ultrasonography disclosed intrahepatic cystic lesions in 20 (25%) patients after hepatic portoenterostomy. The cystic lesions were analyzed morphologically with radiologic imaging studies and histologically in 13 patients who underwent liver transplantation. RESULTS: Fifteen patients had solitary simple cystic lesions, and 5 patients had multiple continuous oval or beaded lesions. Solitary lesions had a fibrotic cyst wall and lacked epithelia. Continuous lesions had a cyst wall covered with biliary epithelia. Thirteen patients with solitary cysts died or required liver transplantation. In 2 patients with continuous lesions, surgical reboring of the porta hepatis could eliminate cystic lesions and jaundice. CONCLUSIONS: Intrahepatic cystic lesions include 2 different conditions. Solitary cysts are retention pseudocysts, which should be referred to as a bile lake, and are associated with poor prognosis. Continuous beaded cysts are dilated bile ducts, which may be reversed. This distinction is important when considering the treatment strategy.

Bile Duct Diseases↗
PubMed2001

Genes encoding bile salt hydrolases and conjugated bile salt transporters in Lactobacillus johnsonii 100-100 and other Lactobacillus species.

Lactobacillus johnsonii strain 100-100 expresses two antigenically distinct conjugated bile salt hydrolases (BSH), alpha and beta, that combine to form native homo- and heterotrimers. This paper reports characterization of loci within the genome that encode this capacity. A locus that encodes BSH beta (cbsH beta), a partial (cbsT1) and a complete conjugated bile salt transporter (cbsT2) was identified previously. DNA sequence analysis at this locus was extended and revealed a complete ORF for cbsT1 and no other ORFs in tandem. The three genes, cbsT1, cbsT2 and cbsH beta, probably constitute an operon; a putative promoter was identified upstream of cbsT1. A second locus that expresses BSH activity in strain 100-100 was identified. Sequence analysis of the clone predicted a 978 nt ORF that did not share tandem organization with other ORFs, was similar in sequence to other BSH genes, and matched, in predicted protein sequence, the first 25 amino acids of BSH alpha. A phenotypic screen for BSH activity and a genetic screen for the cbsH beta locus were performed on 50 Lactobacillus isolates from humans or dairy products. Nearly all of the isolates that were positive for cbsH beta were from human sources. Variability in the BSH phenotype and cbsH beta genotype was identified in isolates of the same species. DNA sequence was obtained and analysed from the cbsH beta locus of one human isolate, L. acidophilus strain KS-13. This organism has cbsT1, cbsT2 and cbs beta genes that are 84, 87 and 85% identical in DNA sequence to those of strain 100-100. DNA sequence identity to strain 100-100 ends in regions flanking this locus. The findings of this study suggest that BSH genes have been acquired horizontally and that BSH activity is important at some level for lactobacilli to colonize the lower gastrointestinal tract.

Amidohydrolases↗
PubMed1973

Bile acids and vitamin A absorption in man: the effects of two bile acid-binding agents, cholestyramine and lignin.

In 14 healthy volunteers, the addition of 12 g cholestyramine to a vitamin A-containing test meal reduced the expected rise in serum vitamin A by 59.5% (p<0.001). By contrast, lignin had no significant effect in 12 subjects. This study confirms the importance of bile acids in vitamin A absorption and the ineffectiveness of lignin as a sequestrator of conjugated bile acids.

Adult↗
PubMed1977

Postprandial serum bile acids in healthy man. Evidence for differences in absorptive pattern between individual bile acids.

The serum concentrations of cholic acid (C), chenodeoxycholic acid (CD), and deoxycholic acid (D) before and after a standardised meal were determined in five healthy female subjects using a highly specific and accurate gas chromatographic-mass spectrometric technique. The C level rose significantly 60 minutes after the meal, reached a peak after 90 minutes, and had returned to the original level after 150 minutes. In contrast, the serum concentrations of CD and D displayed a significant rise by 30 minutes, reached a peak after 90 minutes, but had not returned to fasting levels after 150 minutes. The serum bile acid responses after a meal suggest that there is considerable absorption of dihydroxy bile acids in the proximal small intestine in man.

Adult↗