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PubMed1982

Postprandial serum concentration of individual bile acids in man. Influence of ileal resection.

For the purpose of characterizing the importance of intestinal function in the maintenance of the enterohepatic circulation of individual bile acids, the serum concentrations of cholic acid (C), chenodeoxycholic acid (CD), and deoxycholic acid (D) were determined after a standardized meal. Two groups of subjects were included: 10 healthy controls and 7 patients with ileal resections 20-80 cm long. The bile acid concentrations were determined using a highly specific and accurate gas chromatographic-mass spectrometric technique with the aid of deuterium-labelled internal standards. In patients with ileal resections, only a moderate and early increase was seen in C concentration after a meal, whereas the CD elevation was more pronounced and prolonged. The D concentrations were reduced both after fasting and postprandially. The data indicate that ileal resection results in essentially complete absence of active bile acid resorption and that intestinal uptake via nonionic diffusion is probably dominant, resulting in postprandial rise of mainly CD in serum.

Adult↗

PubMed1992

12 alpha-hydroxylase activity in human liver and its relation to cholesterol 7 alpha-hydroxylase activity.

Interruption of the enterohepatic circulation by cholestyramine causes a several-fold increase in bile acid synthesis, reflected in a stimulation of cholesterol 7 alpha-hydroxylase activity; the synthesis of cholic acid being stimulated to a greater extent than chenodeoxycholic acid. It is not known if this preferential increase in cholic acid is due to an increase of the 12 alpha-hydroxylase activity. The present study aimed at investigating the 12 alpha-hydroxylase activity and its relation to cholesterol 7 alpha-hydroxylase activity in liver microsomes of patients with different levels of cholesterol 7 alpha-hydroxylase activity. Liver biopsies were obtained from four gallstone-free patients, and seven untreated and two cholestyramine-treated gallstone patients undergoing cholecystectomy, and four patients with Crohn's disease undergoing intestinal resection. The combined group of cholestyramine-treated and ileum-resected patients had four times higher cholesterol 7 alpha-hydroxylase activity and two times higher 12 alpha-hydroxylase activity than the other patients. A positive correlation was obtained between cholesterol 7 alpha-hydroxylase activity and 12 alpha-hydroxylase activity (r = +0.69; n = 16). These results indicate that the increased ratio between the synthesis of cholic acid and chenodeoxycholic acid during cholestyramine treatment is due to a compensatory increase of the 12 alpha-hydroxylase activity.

Adult↗

PubMed1984

Steroid effects on uveal transport.

Hydrocortisone (10(-4)M) causes a significant depression of cholic acid accumulation by the isolated rabbit ciliary body-iris while causing little, if any, depression of p-aminohippuric acid uptake and not affecting alpha-aminoisobutyric acid uptake. Because no lag period is present for this inhibition and because cyclohexamide pretreatments fails to eliminate it, the hydrocortisone effect does not appear to be mediated by a protein synthesis mechanism. Deoxycorticosterone (10(-4)M) not only inhibits cholic acid uptake but also depresses p-aminohippuric acid uptake; no deoxycorticosterone effect on alpha-aminoisobutyric acid uptake is seen.

Aminoisobutyric Acids↗

PubMed1981

Effect of bile acid derivatives on taurine biosynthesis and extracellular slime production in encapsulated Staphylococcus aureus S-7.

Various bile acids were added to cultures of encapsulated strains of Staphylococcus aureus growing in serum-soft agar medium of brain heart infusion broth. We examined effects of these compounds on cellular characteristics such as growth type, cell volume index, clumping factor reaction, slime yield, taurine content, and L-(--)-cysteic acid decarboxylase activity. Upon addition to the medium of either taurochenodeoxycholic acid, taurocholic acid (25 to 50 microgram/ml), or cholic acid (10 to 25 microgram/ml), the colonial morphology of taurine-positive cells (strain S-7) was altered from the diffuse to the compact type in serum-soft agar. Also, the titer of the clumping factor reaction increased, while the cell volume index and slime yield were markedly decreased. Tauro-bile acids, including taurocholic acid, taurochenodeoxycholic acid, taurodehydrocholic acid, and taurodeoxycholic acid (50 microgram/ml) inhibited the synthesis of taurine and resulted in decreased L-(--)-cysteic acid decarboxylase activity. Among all of the derivatives cholic acid itself was found to inhibit slime production and L-(--)-cysteic acid decarboxylase activity to the greatest extent. Glyco-bile acid derivatives and taurolicholic acid (50 to 100 microgram/ml) had no effect on L-(--)-cysteic acid decarboxylase activity. Compounds such as glycodeoxycholic acid (50 to 100 microgram/ml) had no effect upon any of the cellular characteristics tested. No effect was observed upon addition of any of these compounds to cultures of the taurine-negative strain (T-26-B). We did find a correlation between the inhibition of taurine biosynthesis and decreased slime production. Electron micrographs indicated that this encapsulated strain was converted to an unencapsulated state in the presence of bile acids.

Bile Acids and Salts↗

PubMed1977

Hepatic lesions and hemolysis following administration of 3alpha, 7alpha, 12alpha-trihydroxy-5beta-cholestan-26-oyl taurine to rats.

Patients with a metabolic block in the conversion of THCA into cholic acid develop cirrhosis and hemolysis, and die of hepatic failure. In these patients, THCA is largely conjugated to taurine (tauro-THCA) and excreted instead of being converted into cholic acid. In the present study, the effects of tauro-THCA on hemolysis, bile flow, and hepatic morphology were evaluated in bile fistula rats. All rats infused with tauro-THCA at rates of 0.25, 0.50 or 0.75 micronmol/min developed hemolysis with hemoglobinuria. A direct toxic effect of tauro-THCA on washed human red blood cell membranes was demonstrated at a concentration of 8 X 10(-4) M. Liver biopsy sections from rats infused for a 2 hr period with tauro-THCA were examined by electron microscopy and showed dilation of the rough endoplasmic reticulum and distortion of mitochondrial membranes. Cholestasis was not induced, since tauro-THCA actually caused a greater choleretic response for a given rate of bile salt excretion than did taurocholate. This study raises the possibility that the clinical liver disease seen in patients with a metabolic block in the conversion of THCA into cholic acid may be caused by tauro-THCA.

Anemia, Hemolytic↗

PubMed1997

Bile acid secretion during synchronized rat liver regeneration.

One major difficulty in interpreting the changes occurring during liver regeneration is the co-existence of non-activated cells and proliferating hepatocytes at all stages of differentiation. The aim of this study was to investigate bile acid (BA) secretion into bile during normal (NLR) and synchronized (SLR) liver regeneration in rats. Regeneration was synchronized by reversible inhibition of ribonucleotide reductase by 10 h treatment with hydroxyurea (HU) shortly after two-third partial hepatectomy. Total BA output as measured by GC-MS increased immediately after partial hepatectomy. This was followed by a further transient enhancement during the next day in the NLR. HU treatment did not significantly modify total BA output, but after releasing synchronized regeneration a marked reduction was observed. This was followed by a recovery to reach values close to those of NLR on day 7 of the regenerative process in SLR. Amidated BA output as measured by HPLC analysis revealed an early enhancement in the proportion of non-conjugated BAs in bile in NLR. However, the profile of conjugated BAs, which was not affected by HU treatment, matched that of total BAs during the first stage of SLR. By contrast, the increase in BA output observed on day 3 of the regenerative process in this group was accounted for by an enhancement in non-conjugated BA secretion. On day 7 of the regenerative process, the proportion of conjugated BA in bile was restored to approximately 100% in this group. Most BA molecules were conjugated with taurine rather than with glycine in all experimental groups, during both NLR and SLR. GC-MS determinations indicated that the magnitude of the cholic acid predominance in all bile samples was significantly modified during liver regeneration. This was increased early after partial hepatectomy and declined toward control values after few (2-3) days. Enhancement in the cholic acid predominance was due to a reduction in the proportion of all other major BAs, above all ursocholic acid and omega-muricholic acid. By contrast, minor BAs in normal control rat bile such as allo-cholic acid were increased during both NLR and SLR, and remained at detectable levels up to day 7. Changes in the proportion of secreted BA species were similar in SLR and NLR except that the early reduction in the proportion of BAs other than cholic acid was more pronounced in SLR and the quantitative importance of the diversity in BA species was recovered earlier in SLR than in NLR. In summary, these results indicate that profound changes in BA secretion during rat liver regeneration do occur. Most of them are probably related to the existence of retro-differentiation/re-differentiation processes which are speeded up by hydroxyurea-induced synchronization of the wave of hepatocyte proliferation.

Animals↗

PubMed2001

Fetal bile acid metabolism: analysis of urinary 3beta-monohydroxy-delta(5) bile acid in preterm infants.

To elucidate the urinary concentration of total bile acids after birth and the profile of the usual and unusual urinary bile acids, especially 3beta-hydroxy-5-cholen-24-oic acid (Delta(5)-3beta-ol), we measured the concentrations of 13 bile acids in the urine from preterm infants vs. full-term controls by gas chromatography-mass spectrometry. The urinary concentration of total bile acids in early preterm infants below 32 weeks of gestational age significantly exceeded that of the late preterm and full-term infants (p < 0.0005). The major urinary bile acids in early preterm infants were cholic acid, 1beta,3alpha,7alpha,12alpha-tetrahydroxy-5beta-cholan-24-oic acid and Delta(5)-3beta-ol. In conclusion, the high urinary concentrations of total bile acids in preterm infants may be due to an overproduction, or more likely to a low hepatic bile acid clearance. An alternative fetal pathway, the acidic pathway, may be a major route of bile acid biosynthesis in preterm infants.

Bile Acids and Salts↗

PubMedDate not supplied

Further studies on the properties of bile acids. I. Bile acid-induced changes of the action of drugs acting on the autonomic nervous system on the heart and blood vessels.

The action of certain drugs on the autonomic system was studied under the influence of bile acids: 3,12-dihydroxycholanic acid (deoxycholic), 3,7,12-trihydroxycholanic acid (cholic), and 3,7,12-triketocholanic acid (dehydrocholic). The experiments were carried out on rat heart in vivo and on isolated rat vessel preparation. It was shown that bile acids reduced the stimulating effect of isoprenaline on rat heart and the relaxing effect on the blood vessels. An inversion of the effects of adrenaline and noradrenaline on the rat heart was observed, and an enhancement of the vasoconstrictor effect of these substances. Under the conditions of this experiment an inversion was noted of the action of acetylcholine on the heart and blood vessels.

Acetylcholine↗

PubMed1994

Specific targeting of antisense oligonucleotides to neutrophils.

The ability of three different hydrophobic ligands (cholic acid, cholesterol, and the tetrapeptide fMLFY) to increase the uptake of an antisense (anti-actin) oligomer into neutrophils was analyzed. In agreement with the literature (Boutorin et al., 1989; Letsinger et al., 1989), we found that cholic acid and cholesterol conjugates greatly enhance the uptake of anti-actin oligomer. When fMLFY is the ligand, the cellular uptake is much less than that of anti-actin oligomer alone, but the biological consequences are much more significant. Our results are consistent with the hypothesis that the fMLFY conjugate of the anti-actin oligomer is internalized via a different route, and reaches its target site most efficiently.

Actins↗

PubMed1996

Promotion of colon carcinogenesis through increasing lipid peroxidation induced in rats by a high cholesterol diet.

To examine the influence of hypercholesteremia on 1,2-dimethylhydrazine (DMH)-induced rat colon cancer, Sprague-Dawley rats received dietary cholesterol (CH, 0-2%) and cholic acid (CA, 0.25%) with or without DMH (20 mg/kg, s.c. injection) for 18 weeks. The rats receiving dietary cholesterol and cholic acid all significantly increased total serum cholesterol and lipids but only a high cholesterol diet (2% CH plus 0.25% CA) decreased the activity of glutathione peroxidase (GSH-Px) and increased the formation of peroxides in the colon (P < 0.01). The rats that received the combination of DMH and high cholesterol diet enhanced these effects. At the end of the experiment, the diet group administered DMH and high cholesterol (2% CH plus 0.25% CA) developed colon adenoma at 50% of incidence in pathological examination, but no colon adenoma formed in the rats treated with high cholesterol alone. It is supposed that a non-carcinogenic agent like cholesterol may potentiate the carcinogenicity of DMH in rats via an increase of lipid peroxidation and decrease in the activity of peroxidase in the target organ.

1,2-Dimethylhydrazine↗

PubMed1981

Cerebrotendinous xanthomatosis: defective liver mitochondrial hydroxylation of chenodeoxycholic acid precursors.

Oxidation of the side chain of 5 beta-cholestane-3 alpha, 7 alpha-diol, 7 alpha-hydroxy-4-cholesten-3-one, and 5-cholestene-3 beta, 7 alpha-diol has been studied in subcellular fractions of liver from a patient with cerebrotendinous xanthomatosis (CTX) and a control subject. All intermediates were efficiently 26-hydroxylated and further converted to the corresponding 26-carboxylated derivatives by the mitochondrial fraction of normal human liver. No such conversion was observed with the mitochondria from the liver of the CTX patient and the control subject. 12 alpha-Hydroxylation of the patient and the control subject. 12 alpha-Hydroxylation of the substrates was very efficient with the microsomal fractions from both subjects. Bases on these and previous findings (Oftebro, H., I. Björkhem, S. Skrede, A. Schreiner, and J. I. Pedersen. 1980. J. Clin. Invest. 65: 1481-1430), it i concluded that the metabolic defect in CTX is a complete lack of mitochondrial C27-steroid 26-hydroxylase. In CTX the precursors of chenodeoxycholic acid are first attacked by the microsomal 12 alpha-hydroxylase and subsequently by the microsomal 25-hydroxylase as an alternate route to cholic acid formation. This explains the increased ratio of cholic acid to chenodeoxycholic acid observed in the bile of these patients. In the normal liver the formation of both cholic acid and chenodeoxycholic acid involves a mitochondrial 26-hydroxylation.

Adult↗

PubMed1983

Sex differences in gallbladder bile acid composition and hepatic steroid 12 alpha-hydroxylase activity in hamsters.

The gallbladder bile acid composition and the activity of the hepatic steroid 12 alpha-hydroxylase were determined in male and female hamsters. Cholic acid, chenodeoxycholic acid, and deoxycholic acid were the major bile acids in both sexes; in addition, 7-ketodeoxycholic acid and lithocholic acid were present. A sex-linked difference in the ratio of cholic acid (plus its metabolites) to chenodeoxycholic acid (plus its metabolite) was observed. The ratio was 1.93 +/- 0.39 in males and 2.74 +/- 0.54 in females. Another sex-linked difference was found in the activity of the 12 alpha-hydroxylase. The extent of the 12 alpha-hydroxylation of 7 alpha-hydroxycholest-4-en-3-one to yield 7 alpha, 12 alpha-dihydroxycholest-4-en-3-one was about two times greater in the microsomal suspension obtained from the liver of female hamsters than in that of male hamsters. A positive correlation between the 12 alpha-hydroxylase activity and the ratio of cholic acid/chenodeoxycholic acid was also observed. These results strongly support the proposal that the activity of the 12 alpha-hydroxylase is the major factor in determining the relative proportion of cholic acid and chenodeoxycholic acid formed from cholesterol in the liver.

Animals↗

PubMed1977

Possible explanations for the differences in secretory characteristics between conjugated and free bile acids.

1. The hepatic extraction fraction and maximum excretory rate of conjugated cholate are greater than those of free cholate (studied after acute taurine depletion); the possibility that this difference might be due to greater bile-to-blood back-diffusion of un-ionized cholic acid (pKa 5-5) compared to that of taurocholic acid (pKa 2) has been investigated by varying the pH of bile by secretin or acetazolamide administration in the anaesthetized dog. 2. The mean biliary pH during free cholate excretion in the control state in twenty-three experiments was 7-5 (at which approximately 1% of cholate is un-ionized). Three to fourfold changes in the hydrogen ion activity of bile (which resulted in changes of the same magnitude in the percentage of un-ionized cholic acid) had no significant effect on the total (mainly free) cholate maximum excretory rate. It is concluded that back-diffusion of un-ionized cholic acid in the bile ducts is not an important determinant of the secretory performance of free cholate. 3. The bile flow rate associated with mainly free cholate excretion is much higher than that associated with taurocholate excretion at the same rate; the extra bile flow appears to arise largely by means that are independent of the osmotic effect of cholate excretion, as the osmotic coefficient (osmolality/total solute concentration) of bile containing mainly free free cholate (calculated directly) was only slightly greater than that of bile containing mainly taurocholate (obtained by extrapolation) at the same total cholate concentration. 4. The peak hepatic excretory rate of taurocholate following the instillation of the entire contents of the gall-bladder of a fasted dog into the distal ileum was only about one fifth of the maximum rate attainable; at the peak rate taurocholate is almost completely removed in the first passage of blood through the liver.

Animals↗

PubMed1987

Lack of regression of preestablished gallstones in mice.

Feeding a high cholesterol, high cholic acid diet to mice for 28 days caused increased concentrations of plasma and liver cholesterol and formation of gallstones. Removal of cholesterol and cholic acid from the diet led to normalization of plasma and liver cholesterol within 28 days. Regression of the preestablished gallstones did not occur within 107 days.

Animals↗

PubMed2002

Comparative study on the enantiomer separation of 1,1'-binaphthyl-2,2'diyl hydrogenphosphate and 1,1'-bi-2-naphthol by liquid chromatography and capillary electrophoresis using single and combined chiral selector systems.

The chiral recognition ability of single and dual selectors, that were used as additives, have been investigated by HPLC and CE. Native beta- and gamma-cyclodextrins, permethylated beta-cyclodextrin, hydroxypropyl-beta-cyclodextrin, cholic acid and taurodeoxycholic acid sodium salts were applied as chiral selectors, whereas the atropisomers of 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate, and 1,1'-bi-2-naphthol served as model compounds. It was found that all investigated selectors, except for gamma-cyclodextrin, display the same affinity pattern for binaphthyl enantiomers, i.e., binding the S more strongly than the R enantiomer. However, the differences in the phase distribution of chiral selectors led to the opposit elution order of enantiomers: with cyclodextrins, the first eluted is S enantiomer, while R is the first eluted for bile salts. Under the conditions studied, cyclodextrins (except gamma-cyclodextrin), as well as cholic acid sodium salts acting singly, enable the separation of 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate enantiomers both by HPLC and CE methods, while 1,1'-bi-2-naphthol enantiomers were resolved only under CE conditions with permethylated cyclodextrin or bile salts. In both techniques the application of dual systems could improve resolution or make it worse (oreven cancel), depending on the sign of enantioselectivity of particular selectors, their concentrations and localization: mobile or stationary phase. It has been found that the mechanism of separation as well as interactions occurring between two selectors may be followed by using combined HPLC and CE methods. The obtained results proved that, as well as beta-CD, TM-beta-D and gamma-CD also form inclusion complexes with cholic acid sodium salts. The reversal of elution order may be realized by two procedures: changing a single selector, i.e., cyclodextrin on cholic acid sodium salt or vice versa, and by changing the proportion of selectors in the combined bile salt-cyclodextrin system.

Bile Acids and Salts↗

PubMed1999

Correlation of neomycin, faecal neutral and acid sterols with colon carcinogenesis in rats.

High fat diets have been implicated in incidence of colon cancer both in epidemiological and animal studies. Present investigation deals with the incidence, location and numbers of large and small bowel tumours induced by 1,2-dimethyl hydrazine (DMH) in rats fed high fat diets and neomycin. Neomycin was used to modify the faecal sterol metabolism and the relationship of the high fat diet and faecal neutral and acid sterols to the large bowel tumorigenesis was evaluated. DMH administered rats were fed with (a) 20% safflower oil; (b) 20% safflower oil and neomycin; (c) 20% safflower oil, cholesterol and cholic acid; and (d) 20% safflower oil, cholesterol, cholic acid and neomycin. Neomycin was found to be associated with both increase and decrease of tumour numbers. The faecal sterols lithocholic and deoxycholic acids were found to have no participation, while cholesterol and cholic acid were found to decrease with increase in tumour numbers. However, faecal coprostanol has been found to have a significant positive correlation with tumorigenesis in all dietary groups. Therefore coprostanol might possibly be associated with colon carcinogenesis in DMH-fed rats and cholesterol metabolism in gut appears to be related to the development of tumours.

1,2-Dimethylhydrazine↗

PubMed2005

Physicochemical properties and biological activities of DEAE-derivatized Sphingomonas gellan.

Physicochemical characteristics and biological activities of Sphingomonas gellan (S-gellan) were investigated. The S-gellan weight fractions of Glc and GlcUA were 0.45 and 0.25, respectively, and the molar ratio of Glc:Rha:GlcUA was approximately 4:2:3. The S-gellan was chemically derivatized with diethylaminoethyl chloride-HCl (DEAE-HCl), and the resulting modified S-gellan contained both positive and negative charges. The elemental and IR analyses were conducted to confirm the successful incorporation of DEAE groups into S-gellan. A large increase in nitrogen fraction was observed from the derivatized S-gellan by elemental analysis. The IR absorption bands induced by C-H, C-N, and C-O-C stretching were noticeable at 2950, 1310-1380, and 1000-1150 cm(-1), respectively, resulting from the DEAE substitution. The characteristic CH3 and CH2 peaks originated from the DEAE group were detected in the 1H NMR spectrum of the derivatized S-gellan as well. The solubility of native S-gellan was improved almost twice from 40% to 75% after DEAE derivatization, while water holding capacity (WHC) drastically decreased from 10026% to 245%. Oil binding capacity (OBC) of S-gellan also significantly dropped from 1528% to 331% after the derivatization. The bile acid binding capacity of S-gellan was indirectly determined by measuring the holding capability of cholic acid inside the dialysis membrane (MWCO 12,000-14,000 Da). Once S-gellan was DEAE derivatized, there was substantial increase in the cholic acid retardation index (CRI). Up to 9 h of dialysis, the derivatized S-gellan released 29.3% less of cholic acid compared to the control group that did not contain S-gellan. From these results of the improved water solubility and stronger bile acid binding capacity, it would be suggested that the DEAE-derivatized S-gellan has more advantages than gellan itself for functional food applications.

Bile Acids and Salts↗

PubMed1984

Styrene exposure and the liver.

The liver functions, as reflected by the serum enzyme activities of aspartate aminotranferase, alanine aminotransferase, and gamma glutamyl transferase and by the concentrations of cholic acid and deoxycholic acid, of 34 styrene-exposed and 34 reference female workers were followed prospectively for a year. The mean age of exposed workers was 34.2 years, mean duration of past exposure 5.1 years. The mean age of the referents was 30.7 years. During the follow-up period blood samples were collected three times for the determinations. The history of possible liver disease and alcohol consumption was ascertained by questionnaire. Altogether 87 samples of both groups were analyzed. The styrene-exposed group did not have higher values for any measurement when compared with those of the referents. Two persons in both groups had one sample with transaminase activities exceeding laboratory reference values. The abnormal values were associated with the use of drugs or alcohol. Cholic acid and chenodeoxycholic acid concentrations were of the same magnitude in both groups.

Adult↗