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Reversed-phase LC assay method for deoxycholate in influenza vaccine.

Sodium deoxycholate is used for the disruption of particles in the manufacturing of some influenza vaccines. Residual deoxycholate in inactivated vaccines is currently determined using a labour-intensive colorimetric method which lacks complete specificity. An alternative assay method for residual deoxycholate in vaccine preparations was developed using reversed-phase LC. Cholic acid was used as internal standard and the ratio of internal standard to test solute was used for all calculations. Prior to LC analysis, deoxycholic acid was concentrated by solid-phase extraction, a procedure that also removed proteinaceous material in vaccine samples. The clean-up/concentration procedure recovery was examined using untreated samples and was found to be quantitative. The linearity range of the LC method was between 3 and 200 micrograms ml-1, with a limit of detection of approximately 0.4 micrograms on column, and a lower limit of quantitation of 1.6 micrograms on column. Replicate assays during intra-and inter-day experiments gave acceptable levels of variability. The DCA content of samples from three lots of influenza vaccine varied between 10 and 16 micrograms ml-1. These values were appreciably lower than those measured spectrophotometrically, indicating the higher specificity of the LC method.

Cholic Acid↗

Hypolipidemic action of taurine in rats.

The effect of taurine on the serum and liver cholesterol and triglyceride levels was studied in rats fed cholesterol plus cholic acid. Four groups of 4 weeks old rats were fed control diet, hypercholesterolemic diet (HCD), HCD + 1% taurine or HCD + 2% taurine for 8 weeks. Addition of taurine in HCD diet showed a significant reduction not only in serum total cholesterol and triglyceride levels but also in liver total cholesterol, lipid and triglyceride contents compared to the animals fed HCD alone. Histological examination of organs of these animals showed severe fatty vacuolation in livers and signet ring type vacuolation in kidneys of rats fed HCD. Taurine showed ameliorating effect on these abnormalities. The animals fed taurine in HCD also showed increased bile and sterol excretion in faeces compared to rats fed HCD alone. Taurine showed significant hypocholesterolemia in rats probably by enhancing the catabolism of cholesterol and reducing the absorption of dietary cholesterol.

Animals↗

Apparent lack of conversion of sitosterol into C24-bile acids in humans.

The metabolic fate of intravenously administered [4-14C]sitosterol was studied in two healthy subjects. In marked contrast to the results of a previous investigation with [22,23-3H]sitosterol, no detectable labeled C24-bile acid products appeared in bile. The first and rate-limiting step in the conversion of cholesterol into bile acids is catalyzed by the liver microsomal cholesterol 7 alpha-hydroxylase. When incubated with human liver microsomes, no detectable 7 alpha-hydroxylation of sitosterol could be demonstrated. This was the case also when using liver microsomes from two subjects treated with cholestyramine, in which case the rate of 7 alpha-hydroxylation of cholesterol was increased three- to sixfold. In order to bypass the rate-limiting step, the metabolic fate of 3H-labeled 7 alpha-hydroxysitosterol was studied in two volunteers. In this case there was a significant conversion into acid products in bile (18-32% excreted in bile during the first 17 h). Although part of the labeled products had chromatographic properties similar to those of cholic acid and chenodeoxycholic acid, further analysis showed that none of the products was identical to chenodeoxycholic acid and only traces at the most could be identical to cholic acid. The results suggest that healthy human subjects, in similarity with other mammalian species studied, have little or no capacity to convert sitosterol into the normal C24-bile acids.

Adult↗

Pylorus and antroseromuscular flap-preserving gastrectomy--a new type of reconstruction after subtotal gastrectomy for treatment of gastroduodenal ulcer: clinical and experimental study.

To avoid motility disturbances after Billroth gastrectomy, the authors designed pylorus and antroseromuscular flap-preserving subtotal gastrectomy (PAFPG). Results showed that gastric motility and emptying time of dogs after PAFPG were close to normal. PAFPG was applied to 125 consecutive patients with gastroduodenal ulcers (gastric ulcer, 15 patients; duodenal ulcer, 94 patients; and combined ulcers, 16 patients) confirmed by barium examination and fibro-gastroendoscopy. All patients recovered smoothly, none of them had postoperative complication. Gastric acid output reduction rates were as follows: basal acid output, 85.05% +/- 8.13%; maximal acid output, 81.76% +/- 10.85%; peak acid output, 81.42% +/- 10.15%. The incidence of postoperative enterogastric reflux (endoscopically) and the concentration of cholic acids in gastric juice were significantly lower in patients after PAFPG than after Billroth I or II gastrectomy. Results suggest that PAFPG reduced gastric acid outputs definitely and overcame adverse motility consequences after Billroth I or II gastrectomy desirably.

Animals↗

Diurnal variation of rat liver enzymes catalyzing bile acid conjugation and sulfation.

This study investigated the diurnal variation in the activity of the hepatic enzymes catalyzing conjugation and sulfation of bile acids. A circadian rhythm was noted in cholic acid : CoA ligase and glycolithocholate sulfotransferase activity. There was no diurnal variation in lithocholate sulfotransferase activity raising the possibility of multiple bile acid sulfotransferases in liver.

Animals↗

Bile acid conjugation in organ culture of human fetal liver.

An organ culture system for prolonged maintenance of human fetal liver has been developed and used to investigate the formation of bile acid conjugates. Multiple liver specimens were obtained from human abortuses and stillbirths ranging from 10 to 29 weeks of gestation. Within 3 hr of hysterotomy, small fragments of liver were established in organ culture. The morphological integrity of the explants was demonstrated by light and electron microscopy. Functional viability was determined by adding radiolabeled primary bile acid to the medium and assaying the taurine and glycine conjugates formed. Primary bile acid was taken up by the tissues, conjugated with taurine and glycine, and secreted into the medium at a constant rate during 10 days in vitro and in constant increments during a selected 24-hr period. The results establish that human fetal liver survives intact for periods up to 10 days in vitro. Taurine conjugates of the primary bile acids predominate throughout gestation and conjugates of cholic acid are synthesized in preference to those of chenodeoxycholic acid. Supplementation of the medium with taurine results in enhanced taurocholate formation with competitive inhibition of glycocholate synthesis, suggesting one acyl transferase system for both taurine and glycine. Finally, in medium supplemented with hydrocortisone there is a reversal of the glycine-taurine ratio seen in fetal liver.

Bile Acids and Salts↗

Sodium retention does not occur at a critical threshold of liver function in alcoholic cirrhosis.

Sodium retention is triggered in rats with experimental liver injury at a critical threshold of liver function. We compared liver function and sodium retention in serially studied patients with alcoholic cirrhosis to determine whether a similar threshold exists in human beings. Antipyrine, caffeine, and cholic acid clearance were measured in 35 men with alcoholic liver disease. Nineteen patients were evaluated on two or more occasions; between studies, 28 remained in sodium balance (group NN), six spontaneously developed sodium retention and ascites formation (group NY), and seven spontaneously lost ascites (group YN). A threshold between patients with and without sodium retention did not exist for any of the clearance measurements. Indeed, values overlapped widely between the two groups. Antipyrine and cholate clearance were significantly reduced in patients with sodium retention, but caffeine clearance was similar in the two groups. Antipyrine and caffeine clearance declined significantly between the first and second study in group NY; cholate clearance did not change. No significant differences were observed between studies in group YN. In several patients of this group, liver function worsened as ascites spontaneously resolved. Impaired liver function commonly but not invariably accompanies sodium retention in patients with cirrhosis. A threshold at which sodium retention occurs or resolves does not exist.

Antipyrine↗

Regulation of bile acid synthesis.

Bile acids are important physiological agents required for disposal of cholesterol and absorption of vitamins and fats. Bile acids are synthesized from cholesterol in the liver. Enterohepatic circulation of bile acids is very efficient and plays an important physiological role in lipid absorption and secretion, and regulation of bile acid biosynthesis and cholesterol homeostasis. Conversion of cholesterol to bile acids requires 15 different enzymatic steps. Four cytochrome P450 enzymes play important roles in bile acid biosynthesis. The classic bile acid biosynthesis pathway starts with modification of the sterol ring and followed by side chain cleavage reactions to synthesize cholic acid (CA) and chenodeoxycholic acid (CDCA), the primary bile acids in most species. The first and rate-limiting enzyme in this pathway is cholesterol 7alpha -hydroxylase, a microsomal cytochrome P450, CYP7A. Another microsomal cytochrome P450 sterol 12alpha-hydroxylase (CYP12) is required for the synthesis of cholic acid. Mitochondrial cytochrome P450 sterol 27-hydroxylase (CYP27) catalyzes sterol side chain oxidation to convert C27 sterol to C24 bile acids. An alternative bile acid biosynthesis pathway (acidic) has been known for sometime but only recently has attracted much attention. In this pathway, side chain oxidation precedes modification of the sterol ring. Mitochondrial sterol 27-hydroxylase (CYP27) catalyzes the first reaction and followed by 7alpha-hydroxylation catalyzed by a microsomal oxysterol 7alpha-hydroxylase (CYP7B). Recent advances in purification and cloning of these major enzymes in the pathways have led to better understanding the molecular basis of regulation of bile acid synthesis and physiological role of the alternative pathways.

Animals↗

Role of bile acids in the pathogenesis of aspirin-induced gastric mucosal hemorrhage in rats.

The simultaneous oral administration of acetylsalicylic acid (64 mg per kg) and taurocholic acid (2.5 mM) to rats induced gastric hemorrhagic mucosal bleeding in 82.4% of animals compared with 29.7% of animals given acetylsalicylic acid alone. Taurodeoxycholic acid and glycocholic acid with acetylsalicylic acid also significantly increased the incidence of gastric hemorrhagic mucosal bleeding compared with the control animals, but cholic acid, chenodeoxycholic acid, and deoxycholic acid did not have a significant effect. Hemorrhagic mucosal lesions were not observed when the bile acids studied were administered alone. These results indicate a possible role for certain bile acids in the pathogenesis of gastric mucosal bleeding after the ingestion of aspirin.

Administration, Oral↗

Soluble oat fiber tends to normalize lipoprotein composition in cholesterol-fed rats.

The effect of oat fiber on VLDL, LDL and HDL composition was investigated by feeding male Sprague-Dawley rats diets containing 1.0% cholesterol and 0.2% cholic acid, and 6% dietary fiber from oat bran, high-fiber oat flour or a processed oat product for 20 d. Compared to cholesterol-fed cellulose controls, all oat fibers altered the response to cholesterol feeding as indicated by 25-45% lower total lipoprotein cholesterol, 40-60% lower VLDL + LDL cholesterol, and 25-40% higher HDL cholesterol contents, P less than 0.01. The effect of the oat fibers on VLDL composition was especially pronounced as demonstrated by 30-65% lower VLDL protein, VLDL apo E and plasma apo B concentrations. The processed oat product which contained 40% more soluble fiber than oat bran or oat flour normalized the lipoprotein profile associated with ingestion of the atherogenic diet significantly more than oat bran or oat flour. Concentration of total lipoprotein cholesterol and distribution of apo E among the VLDL and LDL fractions in the processed oat product group were similar to controls not fed cholesterol. These data indicate that ingestion of oat fiber tends to normalize the lipoprotein profile induced by feeding an atherogenic diet in the rat, and that the hypocholesterolemic effect of oat fiber is associated with its soluble fiber content.

Animals↗

Plasma and hepatic cholesterol levels and fecal neutral sterol excretion are altered in hamsters fed straw mushroom diets.

The effect of the fruiting body and mycelium of Volvariella volvacea (straw mushroom) on the concentrations of plasma lipids, liver cholesterol, fecal neutral sterol and bile acid excretions was investigated in male Golden Syrian hamsters. The hamsters were fed a purified hypercholesterolemic diet (0.1% cholesterol, 10% fat) for 4 wk to elevate plasma lipid concentrations. Twelve hamsters with elevated plasma total cholesterol were randomly assigned to each treatment group: control (5% cellulose), mushroom fruiting body (5%) and mushroom mycelium (5%). After 4 wk of mushroom diet consumption, the plasma total cholesterol, HDL cholesterol, and combined VLDL + LDL cholesterol concentrations (mmol/L) were significantly lower than control in the group fed the fruiting body-diet (40, 38 and 43%, respectively) (P < 0.05). The liver cholesterol levels were significantly lower in both the mushroom fruiting body- and the mycelium-fed groups (28 and 21% in terms of concentration; 39 and 30% in terms of total content, respectively) (P < 0.05) than that in the control group. Fecal neutral sterol excretion in the mushroom fruiting body- and mycelium-fed groups was significantly higher (81 and 74%, respectively) (P < 0.05) than that in the control group. Although no significant differences (P > 0.05) in the excretion of fecal bile acids were observed among groups fed the mushroom diets and the control diet, the mushroom fruiting body diet-fed hamsters apparently had less bacterial degradation of cholic acid as indicated by a significantly greater proportion (P < 0.05) of fecal cholic acid than in controls. They also had a significantly lower proportion of fecal deoxycholic acid (P < 0.05). This study suggests that the fruiting body of the straw mushroom lowers elevated plasma cholesterol in hypercholesterolemic hamsters, whereas the mycelium does not.

Animals↗

Synthesis and characterization of novel analogs of conjugated bile acids containing reversed amide bonds.

New analogs of amino acid-conjugated bile acids were synthesized in which the amide bond was reversed from its normal configuration. These structural isomers of the beta-alanyl conjugates of cholic acid and ursodeoxycholic acid were synthesized by reaction of succinic anhydride with the 24-nor-23-amine derivatives of cholic acid and ursodeoxycholic acid. The chemical and physical properties of these reverse amide conjugated bile acid analogs were compared with those of the normal glycine and beta-alanine conjugates. The reverse amide analogs comigrated with their isomeric beta-alanine conjugates during thin-layer chromatography using a variety of solvent systems. However, the isomeric pairs could be resolved by reversed-phase high performance liquid chromatography, with the reverse amides having greater retention times compared to the beta-alanine conjugates. Critical micelle concentrations, solubility of undissociated forms, and acid dissociation constants were similar for the isomeric pairs. Significant differences in melting points were observed, however, While the isomeric pairs showed no significant differences in sensitivity to base hydrolysis, the reverse amides were not hydrolyzed by the cholylglycine hydrolase from Clostridium perfringens, even after long incubation periods.

Amides↗

Pharmacology of bile acids and their derivatives: absorption promoters and therapeutic agents.

The role of bile acids in pharmacotherapy is reviewed in this article. The therapeutic use of bile has been recognized since ancient times. Previously bile acids were the standard treatment for gallstones where chenodeoxycholic acid and ursodeoxycholic acid were effective in promoting the dissolution of cholesterol gallstones. Today their therapeutic role looks set to expand enormously. Bile acids as absorption promoters have the potential to aid intestinal, buccal, transdermal, ocular, nasal, rectal and pulmonary absorption of various drugs at concentrations that are non-toxic. Keto derivatives of cholic acid, such as 3a,7a,dihydroxy-12-keto-5alpha-cholic acid (sodium salt and methyl ester) are potential modifiers of blood-brain barrier transport and have been shown to promote quinine uptake, enhance the analgesic effect of morphine and prolong the sleeping time induced by pentobarbital. They have also been shown to be hypoglycaemic. Bile acids as therapeutic agents have the potential to produce beneficial effects in sexually transmitted diseases, primary biliary cirrhosis, primary sclerosing cholangitis, gallstones, digestive tract diseases, cystic fibrosis, cancer and diabetes.

Animals↗

Interaction of hemolytic anemia and genotype on hemolysis-induced gallstone formation in mice.

We previously reported that nb/nb mice with hereditary hemolytic anemia spontaneously developed calcium bilirubinate pigment gallstones. To assess the extent to which gallstone formation and bile composition is gene dependent, we transferred the hemolytic process by transplanting bone marrow from nb/nb mice into a nonhemolytic, but histocompatible genotype, W/Wv mice. Hematologic parameters of transplanted W/Wv mice were nearly identical to those of nb/nb mice. Like nb/nb mice, the percentage of transplanted mice with gallstones increased with the duration of the hemolysis and occurred twice as often in female mice as in male mice (37% vs. 19%; p less than 0.05). However, the rate of gallstone formation in transplanted mice was one-third less than that in nb/nb mice (3.6% per month vs. 5.5%; p less than 0.05). Analysis of hepatic bile revealed that (a) marrow-transplanted mice had higher concentrations of unconjugated bilirubin due to hemolysis (p less than 0.05) and of total bile acids determined by the W/Wv genotype (p less than 0.001) than their respective nb/nb counterparts and (b) transplanted mice with stones had a significantly lower proportion of cholic acid (p less than 0.005) and higher proportion of keto-bile acids (p less than 0.005) than transplanted mice without stones, suggesting that the cholic acid concentration may retard stone formation. These data indicate that the hemolytic process is the primary determinant of pigment gallstone formation in these mice and is influenced by the following factors: (a) duration of the hemolytic process, (b) gender, and (c) the genotype that regulates the composition of biliary components like bile acids.

Anemia, Hemolytic↗

Different feedback regulation of hepatic cholesterol and bile acid synthesis by glycodeoxycholic acid in rabbits.

BACKGROUND: To explore the sexual difference in the feedback regulation of hepatic bile acid synthesis, glycodeoxycholic acid (GDCA) was administered to 15 male and 14 female rabbits. METHODS: After bile diversion, GDCA equivalent to the hepatic bile acid influx was infused intraduodenally. Biliary cholic acid output represented bile acid synthesis. Hepatic 3-hydroxy-3 methylglutaryl coenzyme A (HMG-CoA) reductase and cholesterol 7 alpha-hydroxylase activities and steady state messenger RNA (mRNA) levels were determined. RESULTS: GDCA inhibited bile acid synthesis less in female than in male rabbits. Hepatic HMG-CoA reductase activity decreased 39% in males, but increased 48% in females. Hepatic cholesterol 7 alpha-hydroxylase activity decreased similarly in males and females, and mRNA levels decreased 86% in males but were unchanged in females. CONCLUSIONS: (1) Total bile diversion stimulated both hepatic cholesterol and bile acid synthesis by activating the rate-controlling enzymes and increasing mRNA levels. (2) GDCA decreased mRNA levels of HMG-CoA reductase and cholesterol 7 alpha-hydroxylase in males, but mRNA levels did not decrease in females. (3) Bile acid synthesis was sustained in females because continued biosynthesis of cholesterol provided a substrate for cholesterol 7 alpha-hydroxylase and stimulus for enzyme formation.

Animals↗

Altered bile acid metabolism in vegetarians.

Bile acid kinetics were studied in a group of healthy vegetarians and a matched group of healthy control subjects. The daily fractional turnover rate of cholic acid was significantly smaller in the vegetarians than in the controls and deoxycholic acid pool size was significantly smaller in the vegetarians than in the controls. The data suggest that enterohepatic conservation of cholic acid is more efficient in vegetarians than in control subjects resulting in decreased deoxycholic acid input in vegetarian subjects. The possible significance of these data to intestinal oncogenesis is discussed.

Adult↗

Urinary monohydroxy bile acids in young infants with obstructive jaundice.

Using an aluminum oxide column, we fractionated and quantitatively determined urinary monohydroxy bile acids in young infants. For comparison purposes, monohydroxy bile acids were also measured in urine from older children and adults with obstructive jaundice. Lithocholic acid was not found in any specimens of the young infants examined, while 3 beta-hydroxy-5-cholenoic acid was detected in all. In the biliary atresia group, 3 beta-hydroxy-5-cholenoic acid excreted was 0.45+/-0.28 mumol per day (n=7), and in the neonatal hepatitis group, 0.48+/-0.44 mumol per day (n=9). The mean rate of 3 beta-hydroxy-5-cholenoic acid to total urinary bile acids in the biliary atresia group was 2.1%, and 1.3% in the neonatal hepatitis group. In the older children and adults with obstructive jaundice (n=6), 3 beta-hydroxy-5-cholenoic acid was excreted at a mean rate of 3.9% of total urinary bile acids, ranging from 0.63 to 14.81 mol per day. The excretion rate of 3 beta-hydroxy-5-cholenoic acid was related to that of chenodeoxycholic acid (p less than 0.05) in infants, while it was related to that of both chenodeoxycholic acid (p less than 0.01) and cholic acid (p less than 0.05) in older children and adults.

Adult↗

Interaction of beta-cyclodextrin with bile acids and their competition with vitamins A and D3 as determined by 1H-NMR spectrometry.

The interaction of beta-cyclodextrin (beta-CD) with four bile acids, cholic, taurocholic, chenodeoxycholic and lithocholic, was demonstrated by proton-NMR spectroscopy. Lithocholic and chenodeoxycholic acids exhibit a stronger affinity for beta-CD than cholic and taurocholic acids. The affinity of bile acids for beta-CD increases in relation to their hydrophobicity. The competition between these bile acids and the lipophilic vitamins A and D3 in the formation of beta-CD inclusion complexes was studied. These vitamins compete with cholic and taurocholic acids whereas they do not with lithocholic and chenodeoxycholic acids. In the latter case all of the beta-CD present was consumed by the bile acids with the vitamins remaining free in the medium. The affinity of vitamins A and D3 for beta-CD is lower than that of the bile acids. Therefore, when lithocholic or chenodeoxycholic acids are present, the formation of beta-CD inclusion complexes with the vitamins does not occur. The results of this study suggest that depletion of lipophilic vitamins will not occur upon ingestion of beta-CD, thus providing further support for the safety and suitability of beta-CD as an ingredient in foods and orally administered drugs.

Bile Acids and Salts↗