Effect of ethynylestradiol on biliary excretion of bile acids, phosphatidylcolines, and cholesterol in the bile fistula rat

The effects of ethynylestradiol on endogenous bile acids, their capacity to conjugate and excrete intravenously infused cholic acid, the concentrations of biliary cholesterol and lecithin, and the individual molecular species of phosphatidylcholine have been determined in male and female Sprague-Dawley rats. Endogenous biliary bile acids were analyzed by gas-liquid chromatography-mass spectrometry. Eleven bile acids were identified and several minor bile acids, primarily muricholates, could not be completely characterized. After 5 days of treatment with ethynylestradiol (1 mg/kg per day), the percentage of cholic acid decreased and the percentage of 6beta-hydroxylated bile acids, including several monounsaturated species, increased. Ethynylestradiol caused a decrease in bile acid-independent bile flow. Intravenous infusion of cholic acid at a high concentration caused cholestasis in control animals but, after ethynylestradiol treatment, cholestasis developed during the infusion of a much lower concentration of cholate, indicating a lowered threshhold for bile acid-induced cholestasis. In the treated rats, there was a slight increase in excretion of unconjugated endogenous bile acids, and a striking impairment of conjugation of intravenously administered cholic acid. One of the few sex-related differences observed was an increased concentration of biliary phospholipids in untreated male rats. Both phospholipid and cholesterol concentrations in the bile were higher in the treated animals. The molar percentage of cholesterol was always 1-2%, but it was slightly higher in treated animals, especially males. Ethynylestradiol treatment also affected biliary phospholipid by causing a marked increase of phosphatidylcholine species containing palmitic and oleic acid residues and a decrease of species containing stearic and linoleic acid residues. There was no increase in biliary excretion of long chain polyunsaturated species, which might have indicated damage to membranes, in response to ethynylestradiol either alone or with cholic acid infusion. Some of these ethynylestradiol-induced changes in biliary bile acid and lipid excretion are probably peculiar to the rat, but others, such as the increase in molar percentage of cholesterol and cholestasis, may be relevant to disorders in man, especially cholesterol gallstones and idiopathic cholestasis of pregnancy.     

Lipid composition of bile in morbid obesity before and after jejunoileal bypass surgery

Bile cholesterol, phospholipids, total bile acids, individual bile acids, and fatty acid compositions of bile neutral lipids and phospholipids were analyzed before, at one month and at six months following jejunoileal bypass surgery in a series of morbidly obese patients. Preoperative mole percentages of cholesterol and lithogenic indices were high, indicating that biles were supersaturated with cholesterol and outside the micellar solubility zone when plotted on triangular coordinates. At the one month post-operative period percentages of cholesterol and lithogenic indices were significantly increased as compared to the pre-operative state. At six months post-operatively these values had decreased to approximately the pre-operative levels. No changes were observed in percentages of lithocholic acid, but deoxycholic acid decreased to markedly low levels at one month and remained low at the six month post-operative interval. Relative proportions of cholic acid increased, and the ratio of cholic to chenodeoxycholic acid was significantly increased at both post-operative intervals. No significant changes were noted in bile neutral lipid or phospholipid fatty acid composition, indicating that no depletion of essential fatty acids had occurred.     

Serum bile acids and ursodeoxycholic acid treatment in cystic fibrosis-related liver disease

Increased circulating levels of hepatotoxic bile acids may contribute to the cholestasis characteristic of cystic fibrosis-related liver disease. The aims of this study were to compare serum bile acid profiles in patients with cystic fibrosis with and without liver disease, and to evaluate the effect of treatment with ursodeoxycholic acid, a non-hepatotoxic bile acid, on liver biochemistry and serum bile acids in patients with cystic fibrosis-related liver disease. Fasting and postprandial serum bile acid levels were analysed in 15 patients (nine males; median age 18 years) with cystic fibrosis-related liver disease and compared with serum bile acid levels in 18 cystic fibrosis patients (12 males; median age 22 years) without liver disease and 10 control subjects. Fasting and postprandial serum levels of primary and secondary serum bile acids were analysed using high-performance liquid chromatography. Liver biochemistry and serum bile acids were measured in six cystic fibrosis patients with liver disease before and 6 months after treatment with ursodeoxycholic acid 20 mg/kg/day and compared with six control patients with cystic fibrosis-related liver disease. Total fasting and postprandial serum bile acid levels were significantly (P < 0.01) elevated in patients with liver disease compared to those without liver disease and controls. The fasting glycine conjugates of cholic acid, chenodeoxycholic acid and deoxycholic acid, and the fasting and postprandial taurine conjugates of cholic acid and chenodeoxycholic acid were significantly (P < 0.05) elevated in liver disease patients compared to patients without liver disease and controls. After 6 months' treatment with ursodeoxycholic acid, although the serum was significantly saturated with ursodeoxycholic acid and significant improvements in liver biochemistry were observed in the treatment group, there was no significant reduction in the levels of individual serum bile acids. Although circulating levels of potentially hepatotoxic serum bile acids are elevated in patients with cystic fibrosis-related liver disease, improvements in liver biochemistry associated with ursodeoxycholic acid treatment cannot be attributed solely to alterations in levels of endogenous bile acids.     

Sulfate bile acids in germ-free and conventional mice

Sulfated and non-sulfated bile acids were determined in the intestines and in the feces of 7-month-old germ-free and conventional male mice. 1. The bile acid pools in the gall bladder and small intestine were 21.13 mg/100g body weight in germ-free and 11.50 mg in conventional mice. The bile acid pools in the cecum and large intestine of germ-free mice were 3.03 mg/100 g body weight as compared to 1.24 mg in conventional mice. Fecal bile acid excretion was 2.93 mg and 4.12 mg/100 g body weight in 24 h in germ-free and conventional mice respectively. 2. The major bile acids from germ-free mice were cholic acid, alpha-muricholic acid and beta-muricholic acid. Small amounts of chenodeoxycholic and allocholic acid were also present. In addition to these primary bile acids the following secondary bile acids were identified in conventional mice: lithocholic, deoxycholic and omega-muricholic acid. 3. In both germ-free and conventional animals significant amounts of chenodeoxycholic and cholic acid were present as the 7-monosulfate esters. The sulfate esters of these bile acids did not exceed 2% of the total bile acids in the small intestine, but accounted for approximately 50% of the bile acids in the cecum and the large intestine. In contrast, the muricholic acids were nearly exclusively found in the non-sulfate fraction. 4. Alkaline hydrolysis without prior solvolysis of the sulfate esters resulted in loss of bile acids and production of artifacts. Hence, the bile acids of the mouse cannot be analysed by methods involving alkaline deconjugation unless a solvolysis step is included in the procedure.     

Regulation of classic and alternative bile acid synthesis in hypercholesterolemic rabbits: effects of cholesterol feeding and bile acid depletion

The effect of cholesterol feeding (3 g/day) on bile acid synthesis was examined in 10 New Zealand white rabbits (NZW), 8 Watanabe heterozygous and 10 homozygous rabbits with partial and complete deficiencies of LDL receptors. After 10 days of cholesterol feeding, bile fistulas were constructed and bile acid pool sizes were measured. Cholesterol feeding increased plasma and hepatic cholesterol levels in all rabbit groups. Baseline bile acid pool sizes were smaller (P < 0.01) in heterozygotes (139 +/- 3 mg) and homozygotes (124 +/- 30 mg) than NZW rabbits (254 +/- 44 mg). After feeding cholesterol, bile acid pool sizes doubled with increased cholic acid synthesis in NZW and, to a lesser extent, in Watanabe heterozygous rabbits but not in homozygotes. Baseline cholesterol 7alpha-hydroxylase activity in NZW and heterozygotes declined 69% and 53% (P < 0.001), respectively, after cholesterol feeding. Sterol 27-hydroxylase activity reflecting alternative bile acid synthesis increased 66% (P < 0.01) in NZW and 37% in Watanabe heterozygotes but not in homozygotes after feeding cholesterol. Bile fistula drainage stimulated cholesterol 7alpha-hydroxylase activity but not sterol 27-hydroxylase activity in all three rabbit groups. These results demonstrated that dietary cholesterol increased hepatic sterol 27-hydroxylase activity and alternative bile acid synthesis to expand the bile acid pool and inhibited cholesterol 7alpha-hydroxylase in NZW and in Watanabe heterozygous rabbits but not in homozygotes with absent hepatic LDL receptor function. Thus, in rabbits, sterol 27-hydroxylase is up-regulated by the increased hepatic cholesterol that enters the liver via LDL receptors whereas cholesterol 7alpha-hydroxylase is controlled by the circulating hepatic bile acid flux.     

Elevated levels of bile acids in colostrum of patients with cholestasis of pregnancy are decreased following ursodeoxycholic acid therapy [see comemnts

BACKGROUND/AIMS: Intrahepatic cholestasis of pregnancy is characterised by increased levels of serum bile acids. Ursodeoxycholic acid therapy corrects the serum bile acid profile. The aims of this study were: (i) to investigate bile acid excretion into colostrum of women with intrahepatic cholestasis of pregnancy; (ii) to compare concentrations of bile acids in serum and colostrum of non-treated and ursodeoxycholic acid-treated patients; and (iii) to clarify whether ursodeoxycholic acid is eliminated into colostrum following treatment. METHODS: Bile acids were assessed by gas chromatography and high-performance liquid chromatography in serum collected at delivery, and in colostrum obtained at 2+/-1 days after labour, from patients with intrahepatic cholestasis of pregnancy, non-treated (n=9) and treated (n=7) with ursodeoxycholic acid (14 mg/kg bw per day, for 14+/-7 days) until parturition. RESULTS: The concentration of total bile acids in colostrum from patients with intrahepatic cholestasis of pregnancy was higher than in normals (23.3+/-14.8 micromol/l vs. 0.7+/-0.2 micromol/l, p<0.01) and cholic acid was a major species (19.0+/-13.1 micromol/l), reflecting the elevated concentrations in maternal serum (48.9+/-21.0 micromol/l, total bile acids; 33.9+/-16.7 micromol/l, cholic acid. Following ursodeoxycholic acid administration, total bile acids and cholic acid levels in colostrum diminished to 5.7+/-2.5 micromol/l and 3.6+/-1.5 micromol/l, respectively; the proportion of cholic acid decreased (60.6+/-8.0% vs. 76.8+/-5.0%, p<0.05). The ursodeoxycholic acid concentration in colostrum was maintained following treatment; its increased percentage (9.4+/-3.2% vs. 1.0+/-0.2%, p<0.01) was still lower than in maternal serum (20.8+/-3.6%, p<0.05). Only a small proportion (<1%) of lithocholic acid was found in colostrum following therapy. CONCLUSIONS: Bile acid concentrations are elevated and cholic acid is the major species accumulating in colostrum, reflecting serum bile acid profiles in intrahepatic cholestasis of pregnancy. Ursodeoxycholic acid therapy decreases endogenous bile acid levels in colostrum.     

Composition of biliary lipids and kinetics of bile acids after cholecystectomy in man

Postcholecystectomy biliary lipid composition and bile acid kinetics were studied in 24 women and 4 men. Hepatic bile was collected periodically for as long as 4 months without interrupting the enterohepatic circulation and without infecting the biliary system. In 23 patients with cholesterol gallstones, fasting biliary cholesterol made up 10.2% of total lipids in the steady state; in 5 patients with bilirubinate stones, saturation of fasting hepatic bile with cholesterol was lower (8.7% of total lipids). The percentage of deoxycholic acid after cholecystectomy was not higher than that of seven healthy, noncholecystectomized controls. Postcholecystectomy studies of diurnal variation of biliary lipids (7 patients) showed that postprandial hepatic bile had a significantly lower cholesterol saturation than fasting bile. Pool sizes of cholic and chenodeoxycholic acids were low (average 0.4 g/70 kg, each); total synthesis for both bile acids was normal (average 460 mg/day/70 kg), but fractional turnover rates of the two primary bile acids increased after cholecystectomy, probably due to more frequent recycling of the small bile acid pool.     

Biliary bile acids in the gall-bladder and the common bile duct of patients with anomalous pancreaticobiliary ductal junction

The high incidence of biliary tract carcinoma in patients with anomalous pancreaticobiliary ductal junction (APBDJ) with or without choledochal cyst (CC) has been well documented. Twenty-two patients with APBDJ were divided into three groups: Group A, four patients not associated with CC and biliary tract carcinoma; Group B, 13 patients with CC but without biliary tract carcinoma; and Group C, five patients with biliary tract carcinoma (four with and one without CC). Profiles of bile acids in the gall-bladder and/or common bile duct were analysed in these patients and compared with those in the control patients with cholecystlithiasis to examine the hypothesis that the levels of deoxycholic acid (DCA) and lithocholic acid (LCA) are elevated in patients with APBDJ because these secondary bile acids are mutagenic. Bile acids were quantified by gas-liquid chromatography. Total bile acid concentration in the gall-bladder bile was significantly lower in any group with APBDJ than that of controls. In the gall-bladder, increased proportion of chenodeoxycholic acid (CDCA) in Group A and B, decreased proportion of DCA in Group B and increased proportion of cholic acid (CA) in Group C were found in bile. In the bile duct, total bile acid concentration and proportion of DCA were significantly low in bile from Group C and decreased proportion of DCA and increased proportion of CDCA were found in bile from Group B. In both the gall-bladder and hepatic bile, proportion of LCA was not significantly different between any intergroups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Urinary bile acids in population screening for inapparent liver disease

BACKGROUND/AIMS: We performed this study in order to evaluate the diagnostic potential of bile acids in random samples of urine for detection of latent liver disease and to compare a radioimmunoassay for urine bile acids with an enzymatic method that detects bile acid sulfates. This was a prospective cohort study carried out at the VA Medical Center involving 151 adults who attended a Community Health Fair at the hospital and wanted to know if they had liver disease. METHODOLOGY: Urinary bile acids in random specimens of 5-10 ml urine were measured. Radioimmunoassay for primary bile acids and an enzymatic assay with or without sulfated bile acids, all corrected with creatinine for urine flow were performed. Serum primary bile acids were determined by radioimmunoassay. In addition, routine liver profile and clinical examination were carried out. RESULTS: In 78 of 151 subjects there was at least one recent liver profile to match with the urine bile acids. Of these 78, 52 subjects with normal urine bile acids had a normal liver profile. In 11 subjects abnormal urine bile acids were associated with an abnormal liver profile. Nine of these 11 subjects were anti HCV positive, one was HIV positive. Urine bile acids correctly predicted the outcome of routine liver tests in 89% of 78 subjects. In nine cases there was a discordance between urinary bile acids and the liver profile. Failure to correctly predict the liver profile using urine, was reduced from nine subjects to three when urine bile acids were obtained twice at separate intervals. Urine bile acids predicted the outcome of anti HCV testing in 37 subjects with similar accuracy as serum ALT or AST. Urine bile acids correlated with serum bile acids at r=0.96, 0.88 and 0.76 for the radioimmunoassay, enzymatic assay that included sulfated bile acids and enzymatic assay without the sulfates, respectively. CONCLUSION: Bile acids in a random sample of urine are useful for population screening for latent liver disease. Prediction of sub-clinical hepatitis C is comparable to that of serum ALT or AST. Inclusion of bile acid sulfates mildly increases the predictive value of urine. Urine bile acids highly correlate with serum bile acids, indicating their surrogate diagnostic value.     

Serum bile acids in cholestasis of pregnancy

Using routine liver function tests, cholestasis of pregnancy was diagnosed in 86 pregnant women with pruritus. Serum aminotransferase levels were elevated in all cases, ASAT in 99%, and ALAT in 100%. In these patients serum concentrations of cholic, chenodeoxycholic, and deoxycholic acid were determined using a gas chromatographic method and were compared with those in a group of 40 uncomplicated pregnancies. Of these bile acids, cholic acid levels were most frequently elevated, ie, in 92% of the patients. The frequency of elevation of serum levels of alkaline phosphatase, and total and conjugated bilirubin was lower. Thus, it appears that in addition to serum aminotransferase levels the serum cholic acid concentration is a sensitive indicator of cholestasis of pregnancy. The cholestasis series was divided into 3 subgroups of increasing severity of cholestasis as assessed by maternal serum cholic acid levels, and the occurrence of signs of fetal distress was compared between these subgroups. The only intrauterine fetal loss in the series belonged to the severe cholestasis group. The incidence of meconium-stained amniotic fluid also increased significantly in this group, and 21 of the 24 cases with other signs of fetal distress were in the groups of moderate and severe cholestasis.     

Effect of dietary lactose at levels comparable to human consumption on cholesterol and bile acid metabolism of conventional and germfree rats

In recent years, the use of milk products and the concomitant intake of lactose have been tentatively linked to the etiology of cardiovascular disease. An effect of lactose on the microbial modification of acid and neutral sterols has been suggested. In the present study lactose intake, ranging up to 30% of total diet increased beta-muricholic (beta-MC) but not cholic acid concentrations in conventional (CV) rat small intestine to the extent that at the 20% and 30% intake level, the intestinal cholic: beta-MC ratio approached that in germ-free (GF) rats. Total intestinal bile acid (BA) content increased by approximately 1/3, but remained at less than half the value found in GF rats. At lactose intake levels within a range corresponding to the consumption of dairy products often recommended for adult man (5% to 10%) only moderate changes in intestinal, and little change in fecal BA were found during and after the 3 months experimental period. Intestinal beta-MC was increased in the presence and in the absence of an intestinal microflora. Experiments with GF rats fed 10% lactose or 10% maltose indicated that this increase is evoked similarly by both carbohydrates. The slight increase in serum cholesterol levels seen with disaccharide feeding, which became evident only in the GF rats, was again not specific for lactose. No influence was found of lactose feeding on liver cholesterol values. Comparison of CV rats fed nonsterile and radiation-sterilized lactose-containing diets suggested that this mode of sterilization has only a minor influence on the resulting data. When GF experiments are to be incorporated, sterilazation of diet by irradiation with 3.5 to 4.0 X 10(6) Rad is preferable to autoclaving. The present data indicate that no major effect specifically related to a normal dietary intake of lactose on cholesterol and BA metabolism of the adult rat could be demonstrated for the duration of these experiments.     

Lithogenic diet and gallstone formation in mice: integrated response of activities of regulatory enzymes in hepatic cholesterol metabolism

Supersaturation of bile with cholesterol is a prerequisite of the development of gallstones. With the intention to study the integrated response of enzymes regulating hepatic cholesterol metabolism during gallstone formation we used an established model for the induction of cholesterol gallstone disease in mice. Ten mice were fed on a lithogenic diet containing 10 g cholesterol/kg and 5 g cholic acid/kg for 8 weeks and were compared with ten mice fed on a standard pellet diet. Cholesterol crystals or gallstones developed in 90% of gallbladders in treated mice. The lithogenic diet had an inhibitory effect on the rate-limiting enzyme of cholesterol biosynthesis, hepatic 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase (EC 1.1.1.88) activity, 39.6 (SEM 2.8) v. 171.0 (SEM 47.3) pmol/min per mg protein. Cholesterol 7 alpha-hydroxylase (EC 1.14.13.17) activity, regulating bile acid synthesis, was decreased by 80%, and this was assumed to be due to cholic acid in the diet. The cholesterol-enriched diet also induced a tenfold increase in cholesterol esterification rate in the liver, i.e. acyl-CoA:cholesterol acyl transferase (ACAT; EC 2.3.1.26) activity. The total, as well as esterified, cholesterol contents of liver homogenates were significantly higher in cholesterol- and cholic acid-treated mice and correlated well with the ACAT activity (rs 0.72 (P < 0.005), and rs 0.68 (P < 0.01) respectively). A significantly higher ACAT activity was obtained in mice given cholesterol and cholic acid even when the enzyme was saturated with exogenous cholesterol, thus indicating an increased amount of the enzyme. The formation of gallstones is dependent on a delicate balance between lithogenic factors (increased absorption of cholesterol and reduced secretion of bile acids) and defence mechanisms (decreased synthesis and increased esterification of cholesterol). In the specific animal model studied here the two defence mechanisms cannot compensate for the increased absorption of cholesterol and the reduced synthesis of bile acids.     

Decreased fecal bile acid output in patients with coronary atherosclerosis

In most patients with atherosclerosis, the underlying metabolic derangement remains undefined. Animal experiments have suggested that the ability to produce and excrete large amounts of bile acids may be an adaptation mechanism to cholesterol overload protecting against the atherogenic effects of cholesterol. However, there are very few data on bile acid excretion in human atherosclerosis. In the present study, we have investigated fecal bile acid secretion in subjects with and without coronary artery disease. The target group consisted of 30 patients with proven coronary artery disease and the control group consisted of 27 matched subjects without clinical or laboratory evidence of coronary atherosclerosis. Fecal bile acids were measured by gas-liquid chromatography from 24-hr stool collections under a controlled diet. The patients excreted significantly less bile acids than the controls (325+/-135 vs. 592+/-223 mg/day, respectively, p < 0.0001). The difference was primarily due to a reduced excretion of secondary bile acids. Less than 50% of deoxycholate was excreted by patients (180+/-81 mg/day) as compared to controls (367+/-168 mg/day, p < 0.0002), while lithocholic acid excretion was 111+/-62 mg/day in patients vs. 190 +/-70 mg/day in controls (p < 0.005). The fecal output of the two primary bile acids, cholic and chenodeoxycholic acid, did not differ significantly between patients and controls. The fecal output of total bile acids correlated with that of both secondary bile acids in patients as well as in controls. These findings suggest that patients with coronary heart disease are unable to excrete adequate amounts of bile acids to rid themselves of excess cholesterol, even if they are able to maintain a plasma cholesterol level comparable to that of healthy controls.     

Increased neutrophil function induced by bile duct ligation in a rat model

Neutrophil function was studied in rats with common bile duct ligation. Superoxide production stimulated by phorbol myristate acetate, opsonized zymosan or formyl-methionyl-leucyl-phenylalanine; phagocytosis; and chemotaxis were significantly greater in neutrophils from rats with common bile duct ligation than in sham-operated control rats. Enhanced neutrophil activity was observed within 12 hr of bile duct ligation; it remained increased during the 15-day study. Preincubation of neutrophils from control rats with sera of rats with common bile duct ligation did not increase superoxide generation. This suggests that the high superoxide production observed in neutrophils of rats with common bile duct ligation was not an immediate effect of the serum. Neutrophils of rats with portal vein ligation exhibited normal activity, indicating that portal systemic shunting per se is not the underlying mechanism for increased activity. The elevated levels of AST and alkaline phosphatase, indicating liver damage, that appeared within 12 hr of bile duct ligation correlated with the increased superoxide generation.     

Results with six "kit" radioimmunoassays for primary bile acids in human serum intercompared

We examined six radioimmunoassay procedures for measuring primary bile acids in human serum (two 3H-labeled and four 125I-labeled). A significant (p < 0.01) correlation was observed between measurements in the assay both for cholic acid and chenodeoxycholic acid, at low and high concentrations of serum bile acids. All kits were acceptable with respect to accuracy, precision, stability, and analytical recovery. All six procedures gave similar results for chenodeoxycholic and cholic acid in sera of 80 healthy subjects; the agreement was also close when the two primary bile acids were compared with their sum in serum. Normal values ranged from 0.4 to 2.5 mumol/L for conjugated chenodeoxycholic acid and from 0.3 to 1.5 mumol/L for conjugated cholic acid. The 125I assays do not require liquid-scintillation equipment but 125I induces a decrease in the affinity constant of antibody. The sensitivity of the assays was still adequate for measuring bile acids in the serum of healthy fasting persons and liver-disease patients.     

Effect of pectin on serum cholesterol, fecal bile acids and biliary lipids in normolipidemic and hyperlipidemic individuals

Pectin, 40-50 g/day for two weeks administered to nine normolipidemic and hyperlipidemic patients, had no effect on serum triglycerides but did cause a significant decrease in the serum total and unesterified cholesterol of hypercholesterolemic subjects in particular. This was associated with increased excretion of fecal bile acids and total steroids and increased concentration of plasma methyl sterols. Thus, the serum cholesterol reduction by pectin appears to be caused by increased cholesterol elimination into stools as bile acids which is then balanced by enhanced cholesterol synthesis. The composition of biliary bile acids and lipids was not changed and secondary bile acids and sterols decreased inconsistently in feces. The measurement of fecal dry weight suggested that the bulk of the pectin was degraded by bacteria during passage through the intestine. Consequently fecal mass and dry weight were not consistently increased, suggesting that pectin may not be an ideal fibre for increasing fecal bulk in functional colonic disorders.     

Hepatic morphology and bile acid composition of bile and urine during chenodeoxycholic acid therapy for radiolucent gallstones

In 9 patients with radiolucent gallstones, percutanous liver biopsy was performed during treatment with chenodeoxycholic acid in a dose of 500 to 750 mg per day for 3-14 months. In 4 patients pretreatment specimens were available for comparison. No sign of hepatic cellular necrosis or bile duct proliferation was noticed in the biopsies. In 2 patients hepatic steatosis was reduced, and in one patient moderate portal tract inflammation decreased during therapy. Mean values of alkaline phosphatases, alanine aminotransferases, prothrombin, and serum lipids remained unchanged and did not exceed normal limits. In 5 patients the urinary bile acid profile was examined during therapy. Chenodeoxycholic acid constituted 27-50%, lithocholic acid 25-63%, and ursodeoxycholic acid 0-13% of total bile acids in urine. The renal excretion of total bile acids was estimated to be less than two mg per day in each patient. From 86 to 100 per cent of the bile acids in urine was sulfated.     

Bile acids and lipids in isolated rat hepatocytes: content, synthesis, and release, as affected by cholestyramine treatment of the donor rats

Contents of bile acids and lipids, as well as rates of triglyceride synthesis, were determined in isolated hepatocytes from control or cholestyramine-fed rats (denoted below as "control" or "treated" hepatocytes, respectively). During a 3-hr incubation period, total bile acid production was markedly higher in "treated" cells than in "control" cells. With both kinds of cells a marked fall in production rate occurred after the first hour of incubation. Newly produced bile acids appeared in the conjugated form with both kinds of hepatocytes. "Control" cells produced only taurine-conjugated, while "treated" cells made both taurine-conjugated and glycine-conjugated bile acids. However, with exogenous taurine (0.5 mM), the latter cells also produced taurine-conjugated bile acids only. With both kinds of cells, cholic and beta-muricholic acids, but not dihydroxylated bile acids, appeared as newly formed species during the incubation. Addition of dialyzed rat serum to the incubation did not result in a stimulation of bile acid production, with either kind of hepatocytes. "Treated" cells had a slightly higher content of free cholesterol than control cells; contents of other lipids were not different. Fractional release of bile acids and lipids into the medium did not differ between the two kinds of cells. Triglyceride synthesis from added [14C]palmitate (0.5 mM) was 1.8-fold higher in "treated" than in "control" hepatocytes.     

Effect of sodium tauroursodeoxycholate (UR-906) on liver dysfunction in bile duct-ligated rats

We investigated the effect of sodium tauroursodeoxycholate (UR-906) on cholestasis in common bile duct-ligated rats in comparison with the effect of dehydrocholic acid. UR-906 (30-180 mumol/kg) and dehydrocholic acid (180 mumol/kg) were intravenously given once daily for consecutive 20 days in rats and the common bile duct was ligated for the last 10 days. On the next day after the last test drug administration, serum biochemical and plasma hemostatic variables were determined. UR-906 significantly ameliorated the elevation of serum cholesterol, phospholipid, bilirubin and bile acid concentrations in bile duct-ligated rats. UR-906 significantly suppressed the prolongation of plasma prothrombin time and activated partial thromboplastin time. Furthermore, UR-906 significantly suppressed the decreases in plasma coagulation factor II and X activities. However, dehydrocholic acid did not cause significant changes in any of the variables examined in this model. These results suggest that UR-906 has a beneficial effect against cholestasis induced by bile duct ligation in rats and that this drug may be useful in the treatment of clinical cholestatic disorders.     

Hepatoprotection in ethinylestradiol-treated rats is provided by tauroursodeoxycholic acid, but not by ursodeoxycholic acid

Ursodeoxycholic acid (UDCA) and tauroursodeoxycholic acid (TUDCA) have been suggested as potential treatments for drug-induced cholestasis. It was therefore decided to study the effects of administration of UDCA or TUDCA on individual serum bile acid concentration, conventional liver tests and associated hepatic ultrastructural changes in ethinylestradiol-treated (EE) rats mg/kg per day). Control rats were treated s.c. with propylene glycol. EE-treated rats were randomly assigned to receive daily i.p. injections of placebo, TUDCA or UDCA. Four rats in each group were treated for 4 consecutive days, and a second four for 14 days. After 4 days of treatment, the serum levels of cholic acid and taurocholic acid were significantly increased in EE-treated rats. None of the conventional liver tests were significantly different among the four groups. After 14 days of treatment the serum levels of cholic acid, chenodeoxycholic acid, glycocholic acid, glycochenodeoxycholic acid, taurocholic acid, taurochenodeoxycholic acid, bilirubin, alkaline phosphatase and gamma glutamyltransferase were significantly raised in EE and EE plus UDCA treated rats. EE plus TUDCA treated rats, however, had no significant changes in these individual serum bile acids or conventional liver tests. The ultrastructure of livers from EE plus TUDCA treated rats was similar to those of controls. On the other hand, EE and EE plus UDCA rats both showed a significant reduction in sinusoidal microvilli. These results show that treatment of rats for 4 days with EE induces significant rises in the serum concentrations of two individual bile acids and that TUDCA protects against this.(ABSTRACT TRUNCATED AT 250 WORDS)