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Results for “CHOLIC ACID”

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PubMed1980

Bile acid induction specificity of 7 alpha-dehydroxylase activity in an intestinal Eubacterium species.

The addition of cholic acid to growing cultures of Eubacterium species V.P.I. 12708 caused a 25 and 46-fold increase in 7 alpha-dehydroxylation activity using cell extracts or whole cell suspensions, respectively. Bile acid conversion rates using either [14C]-cholic acid or [14C]-chenodeoxycholic acid as substrates increased at approximately the same rate when either cholic or chenodeoxycholic acid was added to growing cultures as inducer. The induction of 7 alpha-dehydroxylase activity was highly specific requiring a free C-24-carboxyl group and an unhindered 7 alpha-hydroxy group on the B ring of the steroid nucleus. Unexpectedly, cholic acid also rapidly induced NADH:flavin oxidoreductase activity in growing cultures of this bacterium.

Bile Acids and Salts↗

PubMed1989

Effects of calcium and bile acid feeding on colon tumors in the rat.

The hypothesis that dietary calcium alters the incidence of colorectal neoplasms was examined in an established model of carcinogenesis. Male Fischer 344 rats (28 days old) were quarantined for 2 weeks. All animals were fed the basal diet (AIN-76) supplemented with cholic acid (0.2%) and/or calcium (1.6%, corresponding to a 3-fold increase above that of the basal diet). N-Methyl-N-nitrosourea (MNU) (2 mg/dose) or saline (control) was given intrarectally to all animals on days 1 and 4 of the experiment. Groups 1-8 were fed the experimental diets concurrently with the first dose of MNU, while groups 9 and 10 were fed the diets 2 weeks prior to MNU (or saline). All animals were sacrificed after 28 weeks. No tumors were observed in the groups given saline (groups 1, 3, 5, 7, and 9). In groups receiving MNU, the addition of cholic acid to the diet (group 4) caused a significant increase in tumors (80% versus 55%), tumors/animal ratio (2.24 versus 0.75), and tumors/tumor-bearing animal ratio (2.80 versus 1.36), group 4 versus group 2, respectively. Increased dietary calcium did not inhibit tumor formation; 68% of animals in groups 6 and 10 had tumors. The combination of dietary cholic acid and calcium (group 8) gave a tumor incidence similar to cholic acid (group 4) alone (72% versus 80%, 2.00 versus 2.24 tumors/animal; 2.77 versus 2.80 tumors/tumor-bearing animal). Most tumors were adenomatous polyps but carcinomas in situ and invasive carcinomas were also present; dietary calcium reduced the number of invasive carcinomas (group 6 versus group 2, P less than 0.04).

Adenocarcinoma↗

PubMedDate not supplied

Normal fasting-state levels of serum cholyl-conjugated bile acids in Gilbert's syndrome: an aid to the diagnosis.

Fasting levels of cholic acid conjugates were determined by radioimmunoassay in the serum of 24 patients with extensively documented Gilbert's syndrome and in 98 healthy controls without unconjugated hyperbilirubinemia. The Gilbert's syndrome patients studied included all three subtypes, as determined from studies of the plasma disappearance kinetics of sulfobromophthalein and indocyanine green. Although patients with structural liver disease severe enough to produce hyperbilirubinemia almost invariably have elevated fasting serum levels of cholic acid conjugates, values were normal in each of the Gilbert's syndrome patients, including patients with metabolic abnormalities in sulfobromophthalein and indocyanine green transport. It is concluded that the measurement of fasting serum levels of cholic acid conjugates is a useful adjunct to the diagnosis of Gilbert's syndrome.

Cholic Acids↗

PubMed1977

Partial purification and characterization of NAD-dependent 7alpha-hydroxysteroid dehydrogenase from Bacteroides thetaiotaomicron.

A NAD-dependent 7alpha-hydroxysteroid dehydrogenase was purified 18-fold over the activity in crude cell extracts prepared from Bacteroides thetaiotaomicron NCTC 10852 using Bio-Gel A 1.5-M column chromatography. A molecular weight of 320 000 was estimated for the partially purified intact enzyme. Substrate saturation kinetics were performed using the 18-fold purified enzyme and the lowest Km values were obtained for 3alpha,7alpha-dihydroxy bile acid and bile salt substrates including chenodeoxycholic acid (Km 0.048 mM), glycochenodeoxycholic acid (Km 0.083 mM) and taurochenodeoxycholic acid (Km 0.059 mM). In contrast, 3alpha,7alpha,12alpha-trihydroxy bile acid and bile salts had higher Km values, i.e. cholic acid (Km 0.22 mM), glycoholic acid Km 0.32 mM) and taurocholic acid Km 0.26 mM). NAD had a Km value of 0.20 mM. The possible physiological significance of 7alpha-hydroxy bile acid oxidation to intestinal bacteroides strains was accessed by determining the rate of conversion of [14C]-cholic acid to 7-ketodeoxy[14C]cholic acid by whole cell suspensions under different incubation conditions. The rate of biotransformation of bile acid to keto-bile acid incubated anaerobically under N2 gas increased markedly when potential electron acceptors such as fumarate (10 mM) or menadione (4 mM) was added exogenously. These results suggest that bile acid oxidation reactions may be linked to energy-generating systems in this bacterium.

Bacteroides↗

PubMedDate not supplied

Malabsorption of liposoluble vitamins in a child with bile acid deficiency.

A male born to first cousins presented at 12 months with hypocalcemic convulsions, rickets, epistaxis due to vitamin K deficiency, and extremely low serum levels of beta-carotene and vitamin A. Liver function was altered moderately (glutamic-oxaloacetic transaminase, 55 U/L; glutamic-pyruvic transaminase, 37 U/L; lactate dehydrogenase, 255 U/L; alkaline phosphatase, 437 U/L). To correct the deficiencies, 8,000 IU vitamin D/day, 10,000 IU vitamin A/day, and intramuscular administration of vitamin K1 were required. At 9 years, he presented signs of neuromuscular affection, and the serum vitamin E level (measured for the first time) was extremely low. Classic lipid malabsorption syndromes (abetalipoproteinemia, chronic cholestasis, mucoviscidosis, coeliac disease, Whipple's disease) were excluded by appropriate examinations. Composition of duodenal bile acids was characterized by undetectable levels of cholic acid metabolites, and only chenodeoxycholic acid metabolites were present. Serum total bile acid concentration was normal, with an atypical low cholic acid/chenodeoxycholic acid ratio and abnormal presence of 3 beta-OH-delta 5-cholenic acid and 6-OH-bile acids. Urinary bile acid composition was also characterized by elevated 6-OH-bile acids. Known enzymopathies of the bile acid synthetic pathway were excluded (cerebrotendinous xanthomatosis, cerebro-hepato-renal syndrome of Zellweger, coprostanic acidemia). Bile acid pool sizes were determined by using stable isotopes: cholic acid pool size [2.90 (N, 32 +/- 16) microM/kg] and chenodeoxycholic acid pool size [10.8 (N, 32.6 +/- 9.9) microM/kg] were extremely low; fractional turnover rates of both bile acids were in a normal range.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed2001

Simultaneous detection of cholyl adenylate and coenzyme A thioester utilizing liquid chromatography/electrospray ionization mass spectrometry.

It has been proposed that acyl adenylate is first formed during activation of the carboxy group into the acyl CoA thioester, an intermediate in the formation of amino acid conjugates. Acyl CoA synthetases may be responsible for this acyl adenylate formation. Recently, we hypothesized the preferential formation of cholic acid adenylate, a major bile acid, preceding production of the corresponding CoA thioester in incubations with rat liver microsomal fractions. To verify this biosynthetic mechanism, monitoring of the incubation mixture of acyl adenylate together with both substrate and acyl CoA thioester is needed. We have developed a detection method for the simultaneous detection of these cholic acid derivatives utilizing liquid chromatography/electrospray ionization mass spectrometry. The CoA thioester of cholic acid forms a chelation complex with the divalent cations remaining on the silica gel packed into the analytical column. Both the addition of a chelating agent, such as EDTA, to the mobile phase and an adjustment of the mobile phase pH to a weak alkaline effectively removed such chelate formation, producing a sharp CoA thioester peak. For a simultaneous mass spectrometric analysis of cholic acid, the corresponding adenylate and CoA thioester, the combined use of a 300 A particle diameter ODS column and 20 mM ammonium acetate buffer (pH 9.0)/2-propanol/acetonitrile as the mobile phase have been proved to be preferable. To avoid any degradation of the chemically unstable adenylate produced in the incubation, we employed a direct injection of the sample onto a preconcentration column. The obtained results indicated a high sensitivity of this method.

Adenosine Monophosphate↗

PubMed1971

Fecal excretion of bile acids: a new technique for studying bile acid kinetics in patients with ileal resection.

The fecal elimination and enterohepatic circulation of bile acid was studied in 11 patients. 10 patients with varying degrees of ileal disease or resection and 1 patient with pancreatic insufficiency and no ileal disease. A new technique was employed which involved the nearly simultaneous administration of cholic acid-(14)C and a nonabsorbable marker. (51)CrCl(3). Each individual stool specimen was collected for 36-96 hr and analyzed separately. Assay of the radioactivity of each isotope allowed the accurate determination of an excretion rate for both cholic acid and (51)Cr. The difference between these rates was used to calculate an absorption coefficient for cholic acid. In addition, bile acid concentration measured by the steroid dehydrogenase technique, and the water content of each stool was determined. THE PATIENTS WERE DIVIDED INTO GROUPS DEPENDING UPON HOW MUCH SMALL INTESTINE WAS RESECTED OR DISEASED: six patients with less than 100 cm of ileal resection or disease (group A), and five patients with more than 100 cm of ileal disease or resection (group B). The (51)Cr excretion rate was similar in the two groups, but cholic acid-(24)C excretion rates were significantly more rapid in group B than in group A. The cholic acid absorption coefficient was essentially normal in the patient with pancreatic insufficiency, moderately decreased in group A patients, and extremely low or zero in group B patients. It was inversely related to the length of intestine diseased or resected. Daily fecal bile acid excretion was normal to twice normal in group A patients and 2-8 times normal in group B patients. In all patients with ileal disease or resection, there was a direct correlation between fecal bile acid, fecal mass, and fecal water. Each millimole of additional bile acid in the stool was associated with an increase in stool water of 11 moles (P < 0.01). These studies show that the kinetics of bile acids in the enterohepatic circulation can be accurately studied in patients with extensive ileal resection. The regular relationship between fecal bile acid and fecal mass and water suggests, but does not prove, a critical role of bile acid in determining stool water.

Administration, Oral↗

PubMed2001

NMR diffusion spectroscopy as a measure of host-guest complex association constants and as a probe of complex size.

The complexes of cyclohexylacetic acid and cholic acid with beta-cyclodextrin were studied by NMR diffusion coefficient measurements. The diffusion coefficient of the 1:1 cyclohexylacetic acid/beta-cyclodextrin complex, K(a) = 1800 +/- 100 M(-1), is slightly slower (3.23 +/- 0.07 x 10(-6) cm(2) s(-1)) than that of beta-cyclodextrin (3.29 +/- 0.07 x 10(-6) cm(2) s(-1)). The diffusion coefficient of the 1:1 cholic acid/beta-cyclodextrin complex, K(a) = 5900 +/- 800 M(-1), is significantly slower (2.93 +/- 0.07 x 10(-6) cm(2) s(-1)) than that of beta-cyclodextrin. The results indicate that caution should be exercised when studying host-guest complexation by the so-called 'single point' technique. A novel data treatment is introduced which takes into account the diffusion behavior of all of the species when determining K(a). Experimentally determined diffusion coefficients of complexes are also a useful probe of the size of host-guest complexes.

Journal Article↗

PubMed1981

Effects of acute and chronic ethanol intake on bile acid metabolism.

Ethanol has been demonstrated to cause aberrations in lipoprotein metabolism, cholesterol synthesis, biliary secretion, and bile acid synthesis. Although there is interdependency of cholesterol and bile acid metabolism, a role of ethanol-induced lipid abnormalities in altering bile acid synthesis has not been found. The direct effects of ethanol administration on bile acid metabolism have been studied in animals and vary with the experimental design. Acutely, ethanol causes decreased bile acid secretion and synthesis, but other effects are less well defined. Chronic ethanol use in man may result in cirrhosis, a condition in which abnormalities of bile acid metabolism have been described in detail. Cholic acid synthesis and pool size are markedly depressed in advanced cirrhosis. Chenodeoxycholic acid synthesis is affected less than cholic acid synthesis, probably because 12 alpha-hydroxylase activity is markedly depressed in cirrhosis, although other steps may also be influenced such as 7 alpha-hydroxylation of cholesterol or availability of cholesterol precursor. The deoxycholic acid pool is depressed probably because of changes in fecal flora. Despite the decrease in total bile acid pool, lithogenicity of bile is not increased in cirrhotic patients because of a concomitant decline in cholesterol and phospholipid secretion. Changes in hepatic blood flow and hepatic extraction cause an increase in plasma bile acid levels which may have clinical relevance.

Animals↗

PubMed1988

Comparison of the binding sites of GSH S-transferases of the Ya- and Yb-subunit classes: effect of glutathione on the binding of bile acids.

We have previously observed that the Ya subunit-containing glutathione (GSH) S-transferases from rat liver exhibit a common high affinity binding site for lithocholic acid, bilirubin, and sulfobromophthalein (BSP) (1984. J. Lipid Res. 25: 1177-1183). Subsequently we found that cholic acid and its amidates bound to a site on the Ya subunit separate for the lithocholic acid/bilirubin site (1986. J. Lipid Res. 27: 955-966). We now have extended this work by showing that amidates of lithocholic acid as well as chenodeoxycholic acid and its amidates competitively displace [14C]lithocholic acid from the Ya subunit. GSH did not inhibit binding of any of the ligands to the high affinity Ya site, but did inhibit binding to the cholic acid site on the Ya subunit. We have also defined the binding sites and effects of GSH on the Yb class of subunits. Lithocholic, chenodeoxycholic, and cholic acids (and amidates) shared a common site on the Yb or Y'b subunit, whereas BSP and bilirubin were bound at a different site. Both the bile acid and organic anion sites on the Yb subunit were inhibited by GSH. The inhibition by GSH in all cases (Ya cholic acid site or Yb bile acid or bilirubin sites) was saturable, of the competitive type, and incomplete at maximal GSH concentrations, suggesting that when GSH binds to its distinct substrate site, it induces a conformational change in the proteins affecting the other binding sites.

Animals↗

PubMed2000

Interaction of three-way DNA junctions with steroids.

DNA aptamers that bind to cholic acid were previously isolated by an in vitro selection method. Secondary structural prediction and deletion-mutant experiments suggested that the cholic-acid binding regions of 19 sequenced clones could form three-way-junction structures. In this article, the secondary structures of the sequenced clones and the structural requirements for binding to cholic acid were evaluated. A course of mutational-analysis and chemical-modification experiments provided strong support for the predicted secondary structure and also indicated that the binding site is located at the branching point of the three-way junction. Sequence analysis revealed that the sequences of the three base pairs flanking the junction of the three stems are highly conserved among selected clones. The evaluation of the relative binding of several bile acids and structurally related steroids with the aptamer was also carried out. The results revealed a broad range of selectivity and preference for hydrophobic steroids rather than for cholic acid upon binding, indicating that the binding is driven by a hydrophobic interaction. The experimental results reported here allowed us to propose a structural model of a binding site formed by three Watson-Crick base pairs.

Base Sequence↗

PubMed1990

Acute effects of ursodeoxycholic and chenodeoxycholic acid on the small intestinal absorption of bile acids.

The effects of ursodeoxycholic acid and chenodeoxycholic acid on the small-intestinal absorption of endogenous bile acids were studied in patients with ileostomies who served as a model to investigate small-intestinal absorption in humans. In the control period, the eight patients excreted 327 +/- 91 (mean +/- standard error of the mean) mumol/8 h cholic acid and 214 +/- 38 mumol/8 h chenodeoxycholic acid by their ileal fluid. Following ursodeoxycholic acid administration (500 mg), ileal excretion of cholic acid increased to 517 +/- 96 mumol/8 h, and that of chenodeoxycholic acid increased to 337 +/- 42 mumol/8 h, indicating decreased absorption of these bile acids. Following chenodeoxycholic acid administration (500 mg), no significant increase of cholic acid excretion was observed, whereas chenodeoxycholic acid excretion increased as expected. It is concluded that following ursodeoxycholic acid administration the absorption of common bile acids from the small intestine decreases markedly. This effect of ursodeoxycholic acid on intestinal absorption of common bile acids probably is responsible for the decrease of their plasma concentrations, the reduction of their pool sizes, the increase of their fractional turnover rates, and most likely also contributes to the increased hepatic synthesis of cholic acid.

Adult↗

PubMed1988

Hydroxylation, conjugation and sulfation of bile acids in primary monolayer cultures of rat hepatocytes.

Hydroxylation of lithocholic, chenodeoxycholic, deoxycholic and cholic acids was studied in monolayers of rat hepatocytes cultured for 76 h. The majority of added lithocholic and chenodeoxycholic acids was metabolized to beta-muricholic acid (56-76%). A small part of these bile acids (9%), however, and a considerable amount of deoxycholic and cholic acids (21%) were converted into metabolites more polar than cholic acid in the first culture period. Formation of these compounds decreased during the last day of culture. Bile acids synthesized after addition of [4-14C]-cholesterol were almost entirely (97%) sulfated and/or conjugated, predominantly with taurine (54-66%), during culture. Sulfated bile acids were mainly composed of free bile acids. The ability of hepatocytes to sulfurylate bile acids declined with culture age. Thus, rat hepatocytes in primary monolayer culture are capable to sulfurylate bile acids and to hydroxylate trihydroxylated bile acids, suggesting formation of polyhydroxylated metabolites.

Animals↗

PubMed1991

Biliary bile acid profiles in familial adenomatous polyposis.

Patients with familial adenomatous polyposis have an excess risk for adenomas and cancers of the upper and lower gastrointestinal tract. In the upper intestine these lesions occur mainly around the ampulla of Vater and they parallel mucosal exposure to bile. In view of this finding and of evidence that bile acids play a role in colorectal carcinogenesis, biliary bile acid profiles were determined in 29 patients with familial adenomatous polyposis (12 before colectomy, 17 after colectomy) and in 28 patients without familial adenomatous polyposis (all with colons in situ). Patients with familial adenomatous polyposis had a higher total biliary bile acid concentration than the others. The bile of patients with polyposis had a greater proportion of chenodeoxycholic acid and a lower proportion of deoxycholic acid than did the bile of patients without polyposis. The ratio of chenodeoxycholic acid and its metabolite lithocholic acid to cholic acid and its metabolite deoxycholic acid, which is related to subsequent bile acid profiles in the colon, was higher in patients with polyposis. Because bile acids influence cellular proliferation, these findings may be of importance with respect to intestinal adenoma and cancer growth.

Adenoma↗

PubMed1997

Purification and characterization of a rat liver bile acid coenzyme A ligase from rat liver microsomes.

In the present study, using the C24 bile acid chenodeoxycholic acid as substrate, rat liver bile acid CoA ligase activity (rBAL) was purified 200-fold from detergent-solubilized microsomes using a combination of Q-Sepharose anion exchange, hydroxyapatite, and CM-Sepharose chromatography. Purified rBAL had a molecular weight of 65 kDa by SDS-PAGE analysis. Gel filtration of purified rBAL indicated that rBAL activity forms a complex with other proteins with an apparent aggregate molecular weight of 243 kDa. A monoclonal antibody raised against the 65-kDa protein and covalently coupled to 6B-Sepharose completely absorbed rBAL activity from a semipurified preparation of rat liver microsomes. Western blot analysis confirmed the elution of the 65-kDa protein from the affinity phase at low pH. Optimum rBAL activity was found at pH 8.5, and activity was dependent on the divalent cation Mg2+. In the presence of 50 microM CoA and 2.5 mM MgCl2, kinetic analysis revealed that the apparent K(m)s of ATP and chenodeoxycholic acid of the purified enzyme were 548 +/- 247 and 18.0 +/- 6.2 microM, respectively, and the apparent Vmax was 9.53 +/- 2.0 nmol min-1 mg protein-1. The formation of chenodeoxycholyl-CoA by rBAL was strongly inhibited by hydrophobic bile acids (the C24 monohydroxy bile acid lithocholic acid and 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid, the C27 homolog of cholic acid), but only weakly by cholic acid. Chenodeoxycholyl-CoA and 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-27-oyl-CoA were confirmed as reaction products of purified rBAL by HPLC-electrospray ionization mass spectrometry.

Animals↗

PubMed1982

Hepatic bile acid elution by albumin and bile acid content in isolated rat hepatocytes.

Bile acid contents were determined for isolated rat hepatocytes. During the course of isolating the hepatocytes, perfusion of rat liver with buffer containing 2% albumin eluted a significant amount of bile acids. The elution was proportional to the volume of the buffer and attributable to albumin in the buffer. The isolated hepatocytes prepared by perfusion with 0.1% albumin buffer, which eluted a negligible amount of bile acids, contained 95 +/- 12 micrograms/10(8) cells of bile acids. The major bile acids were cholic acid (22%), beta-muricholic acid (34%) and hyodeoxycholic acid (10%). Levels of the other bile acids were less than 3%. Peak 8, unidentified but presumed to be a trihydroxycholanoic acid, accounted for 19%.

Animals↗

PubMed1992

The effectual level of ursodeoxycholic acid in therapy for non-advanced chronic cholestasis is fifty percent of total serum bile acids.

Ursodeoxycholic acid therapy (600 mg/day) was evaluated in twelve patients with non-advanced chronic cholestasis. Within four months, ursodeoxycholic acid replaced more than 50% of total bile acids in 8 patients and the reduction of serum gamma-glutamyltranspeptidase, alkaline phosphatase and transaminases averaged 30% or more. The serum levels of chenodeoxycholic acid depend on those of ursodeoxycholic acid, but are not related to those of biochemical parameters. Drug therapy was continued in three poor responders for 2-3 four-month periods. In one case an increase of the serum proportion of ursodeoxycholic acid was associated with a reduction in biochemical parameters. The other two cases had high serum levels of chenodeoxycholic acid and/or cholic acid throughout the entire course of treatment. While the treatment of chronic cholestasis requires an effectual serum proportion of ursodeoxycholic acid, it is important to distinguish endogenous persistent hyper-bile-acidemia from ursodeoxycholic acid-related acidemia.

Adult↗

PubMed1999

Exposure of intestinal epithelial cell HT29 to bile acids and ammonia enhances Mac-1-mediated neutrophil adhesion.

OBJECTIVE: Bile acids and ammonia (NH3/NH4+) are cytotoxic metabolic products, which are known to influence intestinal epithelial functions such as colonic chloride secretion. In this study, we have investigated the effect of bile acids and ammonia on neutrophil-intestinal epithelial adhesive interaction. MATERIALS AND METHODS: Confluently cultured HT29 cells were treated with bile acids or ammonium chloride. Then, 51Cr-labeled neutrophils were added to HT29 cell monolayers, and neutrophil adhesion was assessed by gamma-scintillation counting. RESULTS: Treatment of HT29 cells with 0.1 mM CDCA (chenodeoxycholic acid), DCA (deoxycholic acid), CA (cholic acid) or ammonium chloride but not UDCA (ursodeoxycholic acid) for 30 min increased neutrophil adhesion about 4-folds (p<0.01). The increased adhesion was inhibited 82-91% by 10 microg/ml anti-CD11b and anti-CD18 mAbs (p<0.01), but not by anti-CD11a and anti-CD54 (ICAM-1) mAbs. Interestingly, flow cytometric analysis revealed that ICAM-1 expression on HT29 cells was not changed by bile acid- or ammonia-treatment. In addition, the increased adhesion was inhibited about 65 % by proteinase K-treatment (10 microg/ml, 1 min, p<0.05) but not cycloheximide-treatment (1 microg/ml, 30 min) of HT29 cells. CONCLUSIONS: These observations indicate that exposure of HT29 cells to bile acids or ammonia induces CD11b/CD18 (Mac-1) dependent- but CD11a/CD18 (LFA-1) independent-neutrophil adhesion to intestinal epithelial cells, and ICAM-1 is unlikely involved in the interactions. Furthermore, epithelial ligand(s) for neutrophils are protein molecule(s) which are expressed on the cell surface independent of protein synthesis.

Ammonia↗