BACKGROUND/AIMS: In order to elucidate the possible mechanism of increase of y-glutamyl transpeptidase (y-GTP) activity in cholestatic liver and serum was studied. METHOD: Rats were divided into eight groups: Normal, sham operated control, bile duct obstruction (BDO) alone (BDO group), BDO plus taurocholic acid (TCA) injection (BDO plus TCA group), BDO plus tauroursodeoxycholic acid (TUDCA) injection (BDO plus TUDCA group), choledoco-caval shunt (CCS) operation (CCS groups), CCS plus TCA injection (CCS plus TCA group), and CCS plus TUDCA injection (CCS plus TUDCA group). Y-GTP activity was determined in the serum and liver cytosolic, mitochondrial and microsomal preparations isolated from above experimental rats. The values of Km and Vmax in this hepatic enzyme was measured. RESULT: the activities of liver cytosolic and microsomal y-GTP showed a significant increase in the CCS group. The activities of liver cytosolic, mitochondrial and microsomal y-GTP showed a significant increase in the BDO group. And the activity of serum y-GTP showed a marked increase in teth CCS and BDO poups. However, y-GTP activities in the serum and in liver microsomal prepatation rose more rapidly in the BDO group tban CCS. Y-GTP activity in liver cytosolic and microsomal preparatians, and its Vmax value incmmxl significantly in both CCS plus TCA group, and BDO plus TCA group than each control group, such as CCS and BDO group. On the other hand, the values of Km of the hepatic subcellular y-GTP did not change in the all experimental groups. Sennn y-GTP activity increased significantly in both CCS plus 7CA group, and BDO plus TCA group than each control group. However, these serum and hepatic enzyme activities did not change in both CCS plus TUDCA group and BDO plus TUDCA group. CONCLUSIONS: The above results suggest that 7CA stimulates biosynthesis of the y-GTP in the liver. And the elevations of the serum enzymes activity thought to be caused by increase of hepatocyte membrane permeability by a physical property (detergency) of TCA, which cause the enzyme to leak into the blood in large quantities.
Animals ; Bile* ; Cholestasis ; Cytosol ; gamma-Glutamyltransferase* ; Hand ; Hepatocytes ; Liver* ; Membranes ; Permeability ; Rats* ; Taurocholic Acid

PURPOSE: The possible mechanisms of increased thiol me thyltransferase (TMT) activity in cholestatic rat livers and serum were studied. METHODS: Rats were divided into seven groups: rats receiv ing a sham operation, rats with a bile duct obstruction (BDO) alone (BDO group), rats with BDO plus taurocholic acid (TCA) injection (BDO plus TCA group), rats with BDO plus tauroursodeoxycholic acid (TUDCA) injection (BDO plus TUDCA group), rats receiving a choledoco-caval shunt (CCS) operation (CCS groups), rats receiving a CCS operation plus TCA Injection (CCS plus TCA group), and rats receiving a CCS operation plus TUDCA injection (CCS plus TUDCA group). The TMT activities in the serum and in the hepatic subcellular fractions isolated from these experimental rats were determined. The values of Km and Vmax in this he patic enzyme were measured. RESULTS: The activities of liver mitochondrial and microsomal TMTs as well as the Vmax values of TMT were found to be increased significantly in both the CCS plus TCA and the BDO plus TCA groups, compared with the CCS and BDO groups. On the other hand, the Km values of hepatic subcellular TMT were the same in all experimental groups. The serum TMT activity increased significantly in both the CCS plus TCA and the BDO plus TCA groups, compared with the control, CCS and BDO groups. However, these serum and hepatic enzyme activities were the same in the CCS plus TUDCA and the BDO plus TUDCA groups. CONCLUSION: The above results suggest that TCA stimulates the biosynthesis of TMT in the liver. Also, the elevated TMT activity in the serum is thought to be caused by an increase in membrane permeability of hepatocytes from liver cell necrosis caused by TCA.
Administration, Intravenous* ; Animals ; Cholestasis ; Hand ; Hepatocytes ; Liver ; Membranes ; Necrosis ; Permeability ; Rats* ; Subcellular Fractions ; Taurocholic Acid*

PURPOSE: The possible mechanisms of increased arylamine N-methyl- transferase (AMT) activity in cholestatic rat livers and serum were studied. METHODS: Rats were divided into eight groups: rats receiving a sham operation, rats with a bile duct obstruction (BDO) alone (BDO group), rats with a BDO plus taurocholic acid (TCA) injection (BDO plus TCA group), rats with a BDO plus tauroursode oxycholic acid (TUDCA) injection (BDO plus TUDCA group), rats receiving a choledocho-caval shunt (CCS) operation (CCS groups), rats receiving a CCS operation plus TCA injection (CCS plus TCA group), and rats receiving a CCS operation plus TUDCA injection (CCS plus TUDCA group). The AMT activities in the serum and in the hepatic subcellular fractions isolated from the above experimental rats were determined. The values of Km and Vmax in this hepatic enzyme were measured. RESULTS: The activities of liver mitochondrial and microsomal AMTs as well as the Vmax values of AMT, were found to be increased significantly in both the CCS plus TCA group and the BDO plus TCA group compared with the CCS and BDO groups. On the other hand, the values of Km of hepatic subcellular AMT was the same in all experimental groups. The serum AMT activity increased significantly in both the CCS plus TCA group and the BDO plus TCA group compared with control the CCS and BDO group. However, these serum and hepatic enzyme activities were the same in both the CCS plus TUDCA group and the BDO plus TUDCA group. CONCLUSION: The above results suggest that TCA stimulates the biosynthesis of AMT in the liver. Also, the elevated AMT activity in the serum is thought to be caused by an increase in the membrane permeability of hepatocytes from liver cell necrosis caused by TCA.
Animals ; Cholestasis ; Cholestasis, Extrahepatic ; Hand ; Hepatocytes ; Liver ; Membranes ; Necrosis ; Permeability ; Rats* ; Subcellular Fractions ; Taurocholic Acid* ; Transferases

BACKGROUND/AIMS: Our previous studies of ionization and solubility of unconjugated bilirubin (UCB) yielded inappropriately large differences between the two carboxylic pK'a values of UCB. These data, however, were not ideal due to crystal effects, matastability, impurities of the bilirubin, and imprecision of analyses at low UCB. METHODS: The sodium salt of taurocholate (TC) was purified and dissolved in water to 100 mM. Chloroform (CHCl3) was purified by vacuum distillation. Buffers used were: citrate from pH 4 to 6, phosphate from pH 6 to 8, and borate above pH 8. All had an ionic strength of 0.10. The problems were minimized by rapid solvent partition of UCB from CHCl3 into buffered aqueous NaCl, and a new, accurate assay of low UCB in the aqueous phase which was achieved by concentrating the UCB through back extraction into small volumes of CHCl3. RESULTS: In contrast with the crystal dissolution studies, the two pK'a value were similar. H2B0, not HB-, was the dominant UCB species in the pH range of bile (6.0 to 8.0). The aqueous solubilities of UCB were 90 to 98% less. Less than 0.01% of the bile salt partitioned into the CHCl3 phase and self-association of B= was negligible. UCB solubilities in 50 mM TC were 2 to 10% of those obtained by crystal dissolution, and, up to pH 7.9, were below the maximum UCB concentration in normal human bile. CONCLUSIONS: We suggest that the markedly increased binding of UCB with each ionization step is due to the disruption of the internal hydrogen bonds of the ionized carboxyl groups on interaction with the bile salt. We propose to extend the study of partition to determine the activity and the degradation products of calcium salts of unbound bilirubin fractions.
Bilirubin/*chemistry ; Chloroform ; English Abstract ; Hydrogen-Ion Concentration ; In Vitro ; Solubility ; Solvents ; Taurocholic Acid/*chemistry

BACKGROUND: Although several pathophysiological sequences, such as protease activation, free radical generation, and inflammatory mediator release, have been described in acute pancreatitis, the precise mechanism by which acute pancreatitis is initiated is unkown. Cellular calcium, a key function and also a crucial pathological intracellular messenger in cell injury, appears to be involved in the initiation and development of acute pancreatitis. The aim of this study is to evaluate the role of cellular calcium and therapeutic effect of administering the Ca++ channel blocker nicadipine as an antioxidant. METHOD:Nicardipine, known to be a calcium channel blocker and a most potent antioxidant, was wed as a pretreatment 1 hour before induction of pancreatitis by intraductal infusion of 3% sodium taurocholate or as a post-treatment 1 hour after induction of aucte pancreatitis by retrograde infusion of sodium taurocholate. The net weight of the pancrease, the amounts of s-amylse, GSH and MDA in the pancreatic tissue, and the histologic damage were examined 12 hours after the induction of pancreatitis. RESULTS: Nicardipine administration ameliorated pancreatic edema and reduced the amount of s-amylase compare to untreated necrotizing pancreatitis group. Also, pre- or post-treatment with nicardipine had beneficial protective effect with respect to free radical-induced injury; in particular, pre-treatment with nicardipine was much better. With respect to the histologic findings, pancreatic necrosis, hemorrhage, and neutrophil infiltration were prominent in the necrotizing group, however, in the group treated with nicardipine, the necrosis and hemorrhage were ameliorated remarkably. CONCLUSION:The free oxygen radicals and the intracellular calcium influx were major elements in the pathogenesis of acute pancreatitis, and nicardipine ameliorated pancreatic necrosis and hemorrage and exerted an antioxidant effect. The administration of nicardipine should be considered in the early stage of pancreatitis or in case of risk of pancreatitis.
Antioxidants ; Calcium Channels* ; Calcium* ; Edema ; Hemorrhage ; Necrosis ; Neutrophil Infiltration ; Nicardipine* ; Pancreas ; Pancreatitis* ; Pancrelipase ; Reactive Oxygen Species ; Taurocholic Acid

PURPOSE: To Study the possible mechanisms of change of thiosulfate sulfurtransferase (TST) activity in cholestatic rat liver and serum. METHODS: Rats were divided into seven groups: those receiving a sham operation (Sham group), with a bile duct obstruction (BDO) alone (BDO group), with a BDO plus taurocholic acid (TCA) injection (BDO plus TCA group), with a BDO plus tauroursodeoxycholic acid (TUDCA) injection (BDO plus TUDCA group), a choledocho-caval shunt (CCS) operation (CCS groups), a CCS operation plus TCA injection (CCS plus TCA group) and a CCS operation plus TUDCA injection (CCS plus TUDCA group). The TST activities in the serum and in the hepatic subcellular fractions isolated from above experimental rats were determined. The Km and Vmax values of this hepatic enzyme were measured. RESULTS: The liver cytosolic, mitochondrial and microsomal TSTs activities, as well as the TST Vmax values were found to be significantly decreased in the BDO plus TCA and BDO groups compared to the control group. The activity and Vmax value of the liver cytosolic TST were also found to be significantly decreased in the CCS plus TCA group. Conversely, there was no variation in the Km values of the hepatic enzymes in any of the above experimental groups. The serum TST activities in the CCS plus TCA and BDO plus TCA groups, were significantly increased compared with the control, CCS and BDO groups. However, the serum and hepatic enzyme activities were unchanged in both the CCS plus TUDCA and BDO plus TUDCA groups. CONCLUSION: The above results indicate that TCA represses the biosynthesis of TST in the liver. Also, the elevated TST activity in the serum is most likely due to an increase in the permeability of hepatocytes membrane upon TCA mediated liver cell necrosis.
Administration, Intravenous* ; Animals ; Cholestasis ; Cytosol ; Hepatocytes ; Liver* ; Membranes ; Necrosis ; Permeability ; Rats* ; Subcellular Fractions ; Taurocholic Acid* ; Thiosulfate Sulfurtransferase*

PURPOSE: To Study the possible mechanisms of change of thiosulfate sulfurtransferase (TST) activity in cholestatic rat liver and serum. METHODS: Rats were divided into seven groups: those receiving a sham operation (Sham group), with a bile duct obstruction (BDO) alone (BDO group), with a BDO plus taurocholic acid (TCA) injection (BDO plus TCA group), with a BDO plus tauroursodeoxycholic acid (TUDCA) injection (BDO plus TUDCA group), a choledocho-caval shunt (CCS) operation (CCS groups), a CCS operation plus TCA injection (CCS plus TCA group) and a CCS operation plus TUDCA injection (CCS plus TUDCA group). The TST activities in the serum and in the hepatic subcellular fractions isolated from above experimental rats were determined. The Km and Vmax values of this hepatic enzyme were measured. RESULTS: The liver cytosolic, mitochondrial and microsomal TSTs activities, as well as the TST Vmax values were found to be significantly decreased in the BDO plus TCA and BDO groups compared to the control group. The activity and Vmax value of the liver cytosolic TST were also found to be significantly decreased in the CCS plus TCA group. Conversely, there was no variation in the Km values of the hepatic enzymes in any of the above experimental groups. The serum TST activities in the CCS plus TCA and BDO plus TCA groups, were significantly increased compared with the control, CCS and BDO groups. However, the serum and hepatic enzyme activities were unchanged in both the CCS plus TUDCA and BDO plus TUDCA groups. CONCLUSION: The above results indicate that TCA represses the biosynthesis of TST in the liver. Also, the elevated TST activity in the serum is most likely due to an increase in the permeability of hepatocytes membrane upon TCA mediated liver cell necrosis.
Administration, Intravenous* ; Animals ; Cholestasis ; Cytosol ; Hepatocytes ; Liver* ; Membranes ; Necrosis ; Permeability ; Rats* ; Subcellular Fractions ; Taurocholic Acid* ; Thiosulfate Sulfurtransferase*

We have examined whether bile acids can affect the electrical and mechanical activities of circular smooth muscle of canine colon and ileum, using isometric tension measurement or patch clamp technique. It was found that a dilution of canine bile (0.03 ~ 2% by volume) enhanced or inhibited the amplitude of spontaneous contractions. An individual component of bile, deoxycholic acid (DCA) enhanced the frequency and amplitude of the spontaneous contractile activity at 10(-6) M, while DCA at 10(-4) M inhibited the contraction. Similarly, the response to cholic acid was excitatory at 10(-5) M and inhibitory at 3 X 10(-4) M. Taurocholic acid at 10(-4) M enhanced the amplitude of muscle contraction. Electrically, canine bile at 1% reversibly depolarized the colonic myocytes under current clamp mode. Bile acids also elicited non-selective cation currents under voltage clamp studies, where K+ currents were blocked and the Cl- gradient was adjusted so that ECl- was equal to -70 mV, a holding potential. The non-selective cation current might explain the depolarization caused by bile acids in intact muscles. Furthermore, the bile acid regulation of electrical and mechanical activities of intestinal smooth muscle may explain some of the pathophysiological conditions accompanying defects in bile reabsorption.
Bile Acids and Salts ; Bile* ; Cholic Acid ; Colon ; Deoxycholic Acid ; Gastrointestinal Motility ; Ileum ; Muscle Cells ; Muscle Contraction ; Muscle, Smooth* ; Muscles ; Taurocholic Acid

To investigate the influence of the difference enhancers on the transport mechanism of chlorogenic acid (CGA) across Caco-2 cells model, a RP-HPLC method was adopted to detect the concentrations of CGA. At the concentrations of 20 to 80 microg x mL(-1), the difference of absorption rate constants (K(a)) was not statistically significant. At the concentrations of 40 and 20 microg x mL(-1), the ratios of apparent permeability coefficients (P(app)) of the apical to basolateral and the basolateral to apical were 1.14 and 1.18, respectively. With the effect of enhancers K(a) and P(app) increased, the absorption half-life (T1/2) decreased. CGA passed through the Caco-2 cell membrane mainly by passive transport. It showed that monocarboxylic acid transporter (MCT) could be involved in the across membrane transport process of CGA. Borneol had no effect on the cell membrane transport processes. The order of increasing absorption of CGA caused by the enhancers was sodium lauryl sulphate > sodium taurocholate > carbomer.
Absorption ; Acrylic Resins ; pharmacology ; Caco-2 Cells ; Cell Membrane Permeability ; drug effects ; Chlorogenic Acid ; pharmacokinetics ; Humans ; Sodium Dodecyl Sulfate ; pharmacology ; Taurocholic Acid ; pharmacology

According to World Health Organization, more than 200 million people suffer with chronic hepatitis caused by Hepatitis B virus (HBV) infection worldwide. Chronic hepatitis B causes various complications including liver cirrhosis and hepatocellular carcinoma and approximately 0.5~4.2 million deaths occur annually due to HBV infection. Current therapies such as antivirals and vaccine are often hampered by drug intolerance, side effects, and long-time medication, therefore, the development of powerful anti-HBV drugs is demanded. Recently, sodium taurocholate co-transporting polypeptide (NTCP) receptor was revealed to play a pivotal role in HBV entry into hepatocytes. Cell lines transfected with NTCP receptor enables to analyze HBV life cycle by inducing HBV infection stably, but in vivo models still have some limitations such as high costs, restrictive differentiation, and unveiled cofactors related to human NTCP. Therefore, it requires well-established in vivo models to develop and evaluate novel therapeutic agents targeting NTCP receptor, and viral entry inhibitors that inhibit the early step of viral infection are potent sufficient to substitute for existing antivirals.
Antiviral Agents ; Carcinoma, Hepatocellular ; Cell Line ; Hepatitis B virus ; Hepatitis B, Chronic ; Hepatitis, Chronic ; Hepatocytes ; Humans ; Life Cycle Stages ; Liver Cirrhosis ; Taurocholic Acid ; World Health Organization