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PubMed1995

Continuous spectrophotometric assay of conjugated bile acid hydrolase.

Conjugated bile acid hydrolase (CBAH) refers to a class of enzymes which catalyze the cleavage of the amino acid moieties from conjugated bile acids. These enzymes are significant because of their role in providing substrates for further microbial metabolism in the gastrointestinal tract. They also are used in research laboratories for the deconjugation of bile acids prior to structural analyses. A continuous spectrophotometric assay for CBAH activity was developed using a conjugate of cholic acid and the chromophore, 5-amino-2-nitro-benzoic acid. The free chromophore is detected by virtue of its absorbance at 410 nm. The CBAH from Clostridium perfringens displayed a Km for this substrate of 120 microM. These results demonstrate that this new compound functions as an effective substrate of the enzyme and forms the basis for a convenient and rapid method to monitor CBAH activity.

Amidohydrolases↗

PubMed1998

Poloxamer 407-induced atherogenesis in the C57BL/6 mouse.

Poloxamer 407 (P-407) induces hyperlipidemia in the rat. It was the purpose of this investigation to determine if chronic P-407 administration would produce atherogenic arterial lesions in the C57BL/6 mouse, a strain reported to be susceptible to hyperlipidemia-induced atherosclerotic plaque formation. One injection (i.p.) of P-407 (0.5g/kg) produced hypercholesterolemia in the mouse that peaked at 24 h and returned to control levels by 96 h following treatment. Four groups of mice were maintained: (1) saline injected (C); (2) P-407-injected (0.5g/kg every 3rd day) (P); (3) P-407 injected plus cholic acid in the diet (PC); and (4) mice fed a high cholesterol (CHOL) diet containing cholic acid (HF). Mice from each group were sacrificed following 90, 145, 200, or 300 days of treatment. Plasma lipid concentrations, hepatic CHOL concentrations (145 and 300 day), and aortic atherogenic lesion areas were measured. Plasma CHOL and triglyceride remained at control levels throughout the 300 days in the C group. CHOL of the HF animals plateaued at approximately 225 mg/dl. P-407 produced CHOL concentrations of 600 mg/dl in P mice and 1000-1500 mg/dl in PC animals. There was no lesion formation in C mice. However, by 90 days lesions were present in the three other groups. Size of the lesions progressed through day 300 with the largest lesions (184.33 + 27.99 mu2 x 10(-3)) being present in the PC mice. HF and P animals had lesions of 70.50 + 11.35 and 43.33 + 7.88 mu2 x 10(-3), respectively. This study provides an animal model where atherogenesis has been produced with hyperlipidemia induced using a chemical agent.

Animals↗

PubMed2004

Effects of bile acids on proliferation and production of proteinase activity of Uronema marinum (Ciliophora: Scuticociliatida).

Little is known about the effects of bile acids in relation to infectivity on the biological characteristics of Uronema marinum, a serious opportunistic parasite of farmed olive flounder Paralichthys olivaceus. In this study, we examined the effects of bile acids on the proliferation of U. marinum and on proteinase production in vitro. Proliferation of U, marinum was significantly enhanced by lithocholic acid (LCA) at 30 and 60 pmol, and by chenodeoxycholic acid (CDCA) at 0.06 pmol. In contrast, a significant decrease in proliferation was observed with cholic acid (CA) at 30 and 60 micromol, and with deoxycholic acid (DCA) at all amounts used. Proteinase production from live U. marinum was significantly increased by LCA, whereas CA significantly decreased proteinase production. CDCA and DCA had no effect on proteinase production. Although the types and concentrations of bile acids in the faeces of olive flounder are not known, the present results suggest that bile acids in the culturing water might influence the proliferation and production of proteinases in U. marinum, resulting in an increased possibility of scuticociliatosis in olive flounder farms.

Animals↗

PubMed1983

[Correlation of biliary cholesterol, phospholipids and bile acid compositions and the development of cholesterol cholelithiasis in mice].

A study was attempted to establish a screening method for detecting cholelitholytic ingredients from a wide variety of natural substances. Although mice were selected as a suitable pathological model of cholelithiasis to detect a small amount of the ingredients, all the conventional lithogenic diets caused unfavorable influence on the animals. Therefore, as the first step we formulated a new lithogenic diet consisting of butter, cholesterol, cholic acid, etc, which was adequate for mice. Subsequently, the pathological characteristics and persistence of cholelithiasis were examined in the animals; the changes in bile compositions including free and conjugated bile acids, cholesterol and phospholipids were observed before and at the onset of cholelithiasis. Following confirmation of the stone formation, a normal diet was substituted for the lithogenic diet to likewise assess the bile compositions 4 and 6 weeks later. An increasing tendency for deoxycholic acid, disappearance of chenodeoxycholic acid and decrease in ursodeoxycholic acid were seen under the condition of cholelithiasis. In addition, the cholic acid-glycine conjugate which should not exist in the normal state and the increase in free and tauring-conjugated cholic acid were noticed. The biliary cholesterol level in treated mice increased to about 4 times higher than that in untreated mice, while the biliary phospholipids and total bile acids levels increased to only about 1.5 and about 2 times the control levels, respectively. The incidence of stone formation rose sharply at an experimental period between 2 and 3 weeks after starting the lithogenic diet. Gallstones die not disappear even at the 6th week after substituting a normal diet for the lithogenic one. However, the cholic acid-glycine conjugate disappeared, and deoxycholic acid as well as chenodeoxycholic acid and ursodeoxycholic acid tended to recover to the normal levels in the bile.

Animals↗

PubMed1981

A quantitative evaluation of the conversion of 25-hydroxycholesterol to bile acids in man.

The present study was directed toward providing additional information in man on the nature of a potential alternative pathway to cholic acid not involving an initial 7 alpha-hydroxylation of cholesterol. Two bile fistula patients and one normal subject each received 25-hydroxy[G-3H]cholesterol; [14C]cholic and [14C]chenodeoxycholic acids were also simultaneously administered to one bile fistula patient and normal subject. The labeled 25-hydroxycholesterol was found to be poorly converted to primary bile acids by all three patients; the range of conversion was 9.7 to 18.9%. Cholic acid was favored over chenodeoxycholic acid by a margin of about 1.4/1. It is concluded that a pathway to primary bile acid via the 25-hydroxylation of cholesterol is of minor importance under conditions of normal or accelerated synthesis in man.

Bile↗

PubMed1984

Studies in bile salt solutions. The effect of pH on the cholate and taurocholate stimulation of human milk lipase catalyzed hydrolysis of p-nitrophenylacetate.

The pseudo-first-order rate constants of hydrolysis of p-nitrophenylacetate, catalyzed by human milk lipase, have been measured in solutions of 0.01 mol dm-3 Bistris(2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)-propane-1,3 -diol) buffer at 310.5 K, containing a range of concentrations of sodium taurocholate and sodium cholate, at pH 8.00 and of sodium cholate at pH 6.5. The effect of pH on the activity of the enzyme has been investigated and the stimulation factors of taurocholate and cholate ions and of cholic acid have been calculated to be equal to 5.3, 3.7 and 10.7, respectively. The essential residues for catalytic activity of the enzyme have ionization constants equal to 6.45-6.46 for pK1 and 8.33-8.40 for pK2. The former value is attributed to the presence of a histidine imidazolium group but the identity of the residue leading to pK2 is not proven.

Catalysis↗

PubMed1996

Production and characterization of monoclonal antibodies against the O-5 antigen of Salmonella typhimurium lipopolysaccharide.

Three murine monoclonal antibodies (MAbs) were produced by fusion of P3X63-Ag8.653 myeloma cells and splenocytes of a mouse immunized with heat-attenuated (20 min, 80 degrees C) Salmonella typhimurium cells. MAbs 5A5 and 5B2 were of the immunoglobulin M (IgM) class, while MAb 4A8 was IgG2a. All possessed the kappa light chains. The MAbs were specific to the lipopolysaccharide (LPS) O-5 antigen of Salmonella B serogroup, as determined by electrophoresis followed by immunoblotting. All MAbs recognized the same epitope, as determined by an additive enzyme-linked immunosorbent assay (ELISA), although IgM MAbs exhibited higher avidity than the IgG MAb. ELISA analyses revealed that all three MAbs reacted with S. typhimurium (LPS O:1, 4, 5, and 12) while failing to recognize S. typhimurium var. copenhagen (LPS O:1, 4, and 12). The MAbs reacted equally with live and heat-attenuated Salmonella B serovars containing LPS O-5 antigen. The ability of the MAbs to detect live bacterial cells was further confirmed by transmission electron microscopy. Treatment of bacteria with cholic acid and extremely low pH did not affect antibody binding to S. typhimurium. However, when S. typhimurium cells were exposed to alkaline conditions prior to reaction with all three MAbs, no binding was observed. The use of MAbs to discriminate between S. typhimurium and S. typhimurium var. copenhagen in meat samples was investigated.

Animals↗

PubMed2006

Organic anion recognition of naphthalenesulfonates by steroid-modified beta-cyclodextrins: enhanced molecular binding ability and molecular selectivity.

Two beta-cyclodextrin (beta-CD) derivatives bearing steroid groups (1 and 2) were synthesized by the condensation of mono(6-aminoethylamino-6-deoxy)-beta-CD with cholic acid and deoxycholic acid, respectively, and their original conformations and binding behavior to the organic anion of naphthalenesulfonate derivatives were investigated by using 1H NMR spectroscopy and spectrofluorometric titration in combination with computational methods. The 2D NMR experiments reveal that the steroid groups attached to the beta-CD rim could be deeply embedded in the beta-CD cavity to form the intramolecular (for 1) or intermolecular (for 2) inclusion complexes in aqueous solution. Upon complexation with naphthalenesulfonate derivatives, modified beta-CDs display two obviously different binding modes, that is, the competitive inclusion mode and the induced-fit inclusion mode, which is consistent with the results of molecular modeling study. The two modes and the strict size/shape fitting relationship between the hosts and guests reasonably explain the different binding behaviors and molecular selectivity of host beta-CDs 1 and 2 toward the naphthalenesulfonate guests. Therefore, the cholic acid- or deoxycholic acid-modified beta-CDs could effectively recognize the size/shape of guest molecules as compared with the parent beta-CD, giving good molecular selectivity up to 24.9 for the disodium 2,6-naphthalenedisulfonate/disodium 1,5-naphthalenedisulfonate pair by the host 1.

Anions↗

PubMed1991

Enhanced expression of oncogene-encoded mRNA in a rat model of colon cancer.

We have studied the expression of oncogene-encoded mRNAs in a rat model of colon cancer. In this model, rats are intrarectally administered several low doses of the direct-acting carcinogen, N-methyl-N-nitrosourea (MNU). Tumors, predominantly adenomas, develop 5-7 months following administration of the carcinogen, and many of these progress to carcinomas. Upon assaying the steady-state levels of oncogene-encoded transcripts in normal rat colon, we found that fos and N-myc are highly expressed; H-ras, K-ras, myc, myb, and neu messages are present at lower levels; and N-ras, abl, and raf mRNAs are absent. When we compared transcript levels in rat tumors to those in normal colons from the same animal, we observed a 2-4 fold increase in both myc- and H-ras-encoded mRNAs and a 2-7 fold increase in myb message, but no change in expression of any of the 7 other genes. To test whether this increased expression is related to tumor production or is simply a result of the more rapid cellular turnover observed in tumor tissue, the level of oncogene-encoded transcripts was assayed in colonic mucosae of rats given two treatments known to enhance cell turnover and DNA synthesis in the colon. Neither acute application of MNU nor a diet containing 1% cholic acid caused any change in the level of oncogene-encoded mRNAs in rat colons, thus suggesting that the increased abundance of myc, myb, and H-ras messages in tumors is associated with tumor formation. The enhancement of expression of these genes in adenomas, as well as in carcinomas, further suggests that these alterations occur relatively early during the tumorigenic process.

Adenoma↗

PubMed1986

Endogenous hypertriglyceridemia in a nonobese rat model: plasma lipoproteins and dietary sensitivity.

Sprague-Dawley male rats from the Ivanovas-Sieve colony (IVA-SIV) show higher plasma triglyceride levels compared to the standard Charles River (CR) rats. The triglyceride enrichment occurs primarily in the very-low-density lipoproteins (VLDL), otherwise of a normal % composition, suggesting that the number of particles is increased, rather than their triglyceride (TG) content. High-density lipoprotein (HDL) particles, corresponding to HDL1, appear to be increased in the IVA-SIV rats, as confirmed by rate-zonal ultracentrifugation. The apoprotein composition of isolated lipoproteins (apo B content and isoelectric focusing pattern), does not differ in the two strains. The IVA-SIV rats are remarkably more TG inducible, compared to the standard CR. This can be shown with fructose loading and with a cholesterol-cholic acid diet. The plasma TG increase, after Triton administration, indicative of the VLDL-TG production, is fourfold higher in the IVA-SIV, compared to the CR rats. These findings provide evidence for some similarities between the IVA-SIV rat and human endogenous hypertriglyceridemia, and suggest an increased TG biosynthesis in this model.

Animals↗

PubMed1995

[Bile-secreting function of the liver in patients with chronic alcoholism and ways of correcting it].

The examinations showed the differences in bile secretion and biochemical composition of bile in patients with chronic alcoholism II and III stages (respectively 1 and 2 groups of patients). The patients of group 1 have hypotonic gall-bladder with normal or in some cases increased speed of bile secretion with low contents of cholic acid, cholesterol and bilirubin. A type of bile secretion in patients group 2 is hypotonic-hypokinetic with patterns of bile stagnation. Treatment of patients of group 1 by cholenzyme and patients of group 2 by enterosorbent cholysorb promoted normalisation of intestinal circulation of bile components. Cholenzyme is remedy of compensation therapy and cholisorb allows to remove the bile stagnation.

Adult↗

PubMed1993

Synthesis and 29-14C-labeling of 3 alpha, 7 alpha, 12 alpha-trihydroxy-27-carboxymethyl-5 beta-cholestan-26-oic acid. A bile acid occurring in peroxisomal diseases.

The synthesis and 14C-labeling of 3 alpha, 7 alpha, 12 alpha-trihydroxy-27-carboxymethyl-5 beta-cholestan-26-oic acid by two different approaches is described. One of them involves chain elongation of cholic acid via Wittig-Horner condensation of its formylated 24-aldehyde with tetraethyl phosphonoglutarate. The resulting cholestenoate, on deprotection and hydrogenation, affords the unusual C29 bile acid in good yield. An alternative procedure consists in a malonic ester synthesis starting from the formylated 24-alcohol which, after conversion into a mesylate, is reacted with sodium salt of 2-carboethoxy-gamma-butyrolactone. Alkaline hydrolysis, decarboxylation, esterification with diazomethane and selective tosylation of the newly introduced primary hydroxyl function give a C28 precursor, which is easily chain-elongated into a labeled or unlabeled C29 bile acid by reaction with cyanide and hydrolysis. Due to the easy lactonization of some of the C28 intermediates, the latter method provides a better way for introducing a C-29 label than the sequence usually employed for carboxyl labeling of bile acids and consisting in a decarboxylative halogenation of the parent acid followed by substitution of the norhalogenide with [14C]cyanide and hydrolysis. The structure of the synthesized acid or its dimethyl ester is confirmed by 13C nuclear magnetic resonance spectroscopy and mass spectrometry, and is also shown by gas liquid chromatography to be identified with an authentic sample of biosynthetic C29 dioic bile acid extracted from body fluids of Zellweger patients.

Aldehydes↗

PubMed1998

Antihypercholesterolemic action of a traditional Chinese medicine (Kampo medicine), Ogi-Keishi-Gomotsu-To-Ka-Kojin.

The effect of Ogi-Keishi-Gomotsu-To-Ka-Kojin (OKGK), a traditional Chinese herbal medicine (Kampo medicine), on cholesterol metabolism was studied in male Sprague-Dawley rats. Intake of OKGK at doses of 1.38 g/kg for 4 weeks significantly reduced total cholesterol levels in the serum and liver of hypercholesterolemia rats fed a cholesterol-enriched diet. OKGK suppressed cholesterol absorption through the intestine and stimulated excretion of cholesterol into feces as bile acids. Biochemical study indicated that OKGK treatment enhanced cholesterol 7alpha-hydroxylase activity the rate limiting enzyme of cholic acid synthesis, in the liver without any effect on the rate limiting enzyme of cholesterol synthesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. Further, cholesterol-enriched diet containing cholic acid suppressed cholesterol 7alpha-hydroxylase activity, whereas OKGK administration reversed the suppression. In conclusion, these results supported the idea that OKGK may be an effective agent for treatment of patients with hypercholesterolemia.

Animals↗

PubMed1994

Unconjugated faecal bile acids in familial adenomatous polyposis analysed by gas-liquid chromatography and mass spectrometry.

Previous studies have suggested reduced formation of secondary bile acids in patients with familial adenomatous polyposis (FAP). Developments in the collection, extraction and analysis of faecal bile acids as well as in the accurate diagnosis of FAP by DNA markers prompted reinvestigation of this hypothesis. The median (interquartile range (i.q.r.)) faecal bile acid concentration (3.69 (1.66-5.36) mumol per g dry weight) and daily excretion rate (60.5 (29-149) mumol per g per 24 h) in ten patients with FAP were similar to those of nine control subjects (3.31 (0.65-8.38) mumol per g dry weight and 30.1 (7.9-228) mumol per g per 24 h). Although the median (i.q.r.) concentration of only one bile acid (12-oxo-lithocholic acid) was significantly different between patients with FAP and controls (49 (34-70) versus 0 (0-20) nmol per g dry weight, P = 0.006), the derivatives of chenodeoxycholic acid (3.35 (1.76-5.32) versus 0.51 (0.13-2.37) mumol per g dry weight, P = 0.02) and cholic acid (1.63 (0.42-2.34) versus 0.80 (0.13-3.57) mumol per g dry weight, P = 0.006) were increased in those with polyposis. These results show increased bacterial biotransformation of faecal bile acids in patients with FAP.

Adenomatous Polyposis Coli↗

PubMed1986

[Entero-gastric reflux after distal stomach resection--an animal experiment study].

UNLABELLED: The experiments were carried out in 125 Wistar rats. The entero-gastric reflux was estimated quantitatively with reference to the bilirubin and the cholic acid (radiolabeled by C 14). The animals were submitted to distal partial gastrectomy in groups after Billroth I operation, after Billroth II operation with and without enteroanastomosis, as well as Billroth II operation with enteroanastomosis and vagotomy. RESULTS: The statistical difference was significant between Billroth I and Billroth II operation with clear smaller reflux in Billroth I. The added enteroanastomosis decreased or increased the reflux of some animals at a time. The additional vagotomy reduced the number of the anastomotic ulcer.

Animals↗

PubMed1996

Dieldrin pretreatment alters [14C]dieldrin and [3H]7,12-dimethylbenz[a]anthracene uptake in rainbow trout liver slices.

We previously demonstrated that pretreatment of rainbow trout with the organochlorine insecticide dieldrin altered in vivo disposition of a subsequent [14C]dieldrin dose. This was not explained by changes in total lipid content or the activity of common xenobiotic metabolizing enzymes. We hypothesized that dieldrin induced hepatic proteins responsible for organochlorine (OC) sequestration, transport, or excretion and that these changes reflected an adaptive response of trout to OC exposure. Here, uptake of 1.18 microM [14C]-dieldrin by precision cut liver slices was increased by dieldrin pretreatment of rainbow trout. Uptake of 0.118 and 1.18 microM [3H]-7,12-dimethylbenz[a]anthracene (DMBA) and efflux of 0.118 microM [3H]DMBA were significantly increased in slices from dieldrin-pretreated trout. Liver slice uptake of 10 but not 1.18 microM [3H]-estradiol and [3H]cholic acid was significantly increased by dieldrin pretreatment. There were no such significant differences for [3H]cholesterol, [3H]cholesterol-oleate, or [3H]oleic acid uptake. Dieldrin pretreatment did not alter hepatic microsomal metabolism of [3H]DMBA or [14C]benzo[a]pyrene or content of six cytochrome P450 isozymes, as quantitated by Western Blot analysis. These results provide further evidence that altered disposition of [14C]dieldrin and [3H]DMBA in dieldrin-pretreated trout was not explained by microsomal enzyme induction but reflected altered processes integral to hepatocellular transmembrane kinetics. These changes may have important implications for OC bioaccumulation by rainbow trout and demonstrate an interaction between dieldrin and DMBA in the absence of cytochrome P450 system induction.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1997

Inhibition of the hepatic uptake of paracetamol sulphate by anionic compounds.

The effect of anionic compounds on the hepatic uptake of paracetamol sulphate, a conjugative metabolite of paracetamol, has been studied. Hepatic uptake of paracetamol sulphate by isolated hepatocytes was inhibited by bromosulphophthalein, dibromosulphophthalein and p-nitrophenyl sulphate, but not by probenecid or cholic acid. Bromosulphophthalein and dibromosulphophthalein also inhibited the uptake of paracetamol sulphate in the rat isolated perfused liver. Saturable uptake of paracetamol sulphate was also observed in the absence of inorganic sulphate. The uptake of paracetamol sulphate was reduced by 1 and 10 mM inorganic sulphate. Bromosulphophthalein and p-nitrophenyl sulphate inhibited the uptake of paracetamol sulphate in the absence of inorganic sulphate. These results indicate that paracetamol sulphate shares a transporter with bromosulphophthalein, dibromosulphophthalein and p-nitrophenyl sulphate, all of which contain the sulphate or sulphonate group. Therefore, the sulphate or sulphonate moiety might be crucial for interaction with the transporter, and mutual inhibition of hepatic uptake among these compounds is likely.

Acetaminophen↗

PubMed1996

Homocysteine induced arteriosclerosis-like alterations of the aorta in normotensive and hypertensive rats following application of high doses of methionine.

Following oral administration of methionine in high doses to normotensive (NR) and spontaneously hypertensive (SHR) rats, its degradation product, homocysteine (HC), which is markedly elevated in serum, exerts an angiotoxic action directed to the aorta. This is accompanied by considerable loss of endothelium and degeneration, partly with dissolution of the media cells with formation of characteristic processes of the degenerating mitochondria, and by elevated HC and cystathion (CT) values in the aortic wall. At the arterial vessels of other organs similar alterations did not occur. There are quantitative differences between NR and SHR. In SHR, serum shows higher HC and CT concentrations than in NR, and the methionine-related aortic alterations are considerably more pronounced and develop earlier, with the additional formation of connective tissue. Here, a certain dependence on the methionine dose is noted, in contrast to NR, for which the magnitude of the reaction appears to be more related to the length of time of methionine application. Additional administration of atherogenic substances (cholestane-3 beta, 5 alpha, 6 beta-triol, cholesterol, angiotensin II, cholic acid with methylthiouracil) in SHR causes an exacerbation of the methionine-related aortic alterations. Only cholestane-triol has the same effect on the aortic wall in NR and SHR, with more accentuation in SHR. Cholestane-triol has, in NR as well as in SHR, a high coincidence with methionine-induced morphological reactions including the formation of mitochondrial processes. Simultaneous application of these two substances did not cause a potentiation of the effect. High doses of cholesterol bring about aortic alterations in SHR but not in NR. Thus, in addition to the disorder of fat and carbohydrate metabolism, disturbed protein metabolism is of decisive importance as a risk factor for coronary and other vascular diseases.

Angiotensin II↗