Effect of tauroursodeoxycholate feeding, with or without taurine supplementation on hepatic bile acids and cholesterol metabolism in the hamster (original) (raw)
Related papers
Taurine increases bile acid pool size and reduces bile saturation index in the hamster
Journal of lipid research, 1987
There is evidence that increased availability of taurine enhances the proportion of taurine-conjugated bile acids in bile. To explore the possibility that taurine treatment could also influence hepatic cholesterol and bile acid metabolism, we fed female hamsters for 1 week and measured both the biliary lipid content and the microsomal level of the rate-limiting enzymes of cholesterol and bile acid synthesis. In these animals the cholesterol 7 alpha-hydroxylase activity was significantly greater in respect to controls (P less than 0.05). The total HMG-CoA reductase activity, as well as that of the active form, was similarly increased. The stimulation of 7 alpha-hydroxycholesterol synthesis was associated with an expansion of the bile acid pool size in taurine-fed animals. Taurine feeding was observed to induce an increase in bile flow as well as in the rate of excretion of bile acids, whereas the secretion rate of cholesterol in bile was decreased. As a consequence, the saturation in...
Clinical and experimental pharmacology & physiology, 2015
This study was designed to investigate the effects of dietary taurine on cholesterol metabolism in high cholesterol-fed rats. Male Sprague-Dawley rats were randomly divided into 2 dietary groups (n=6 in each group): a high-cholesterol diet containing 0.5% cholesterol and 0.15% sodium cholate, and a high-cholesterol diet with 5% (w/w) taurine. The experimental diets were given for two weeks. Taurine supplementation reduced the serum and hepatic cholesterol levels by 37% and 32%, respectively. Fecal excretion of bile acids was significantly increased in taurine-treated rats, compared with untreated rats. Biliary bile acid concentrations were also increased by taurine. Taurine supplementation increased taurine-conjugated bile acids by 61% and decreased glycine-conjugated bile acids by 53%, resulting in a significant decrease in the glycine/taurine (G/T) ratio. Among the taurine-conjugated bile acids, cholic acid and deoxycholic acid were significantly increased. In the liver, taurine s...
Metabolism of Taurolithocholic Acid in the Hamster
Journal of Biological Chemistry, 1967
Sodium taurolithocholate-24J*C was infused intravenously into bile fistula hamsters and one rat. More than 95% of the administered l*C was recovered in bile. The bile of the rat contained a variety of metabolites comparable to those lmown to occur after lithocholic acid administration. Only one metabolite, taurochenodeoxycholate-l*C, was identified in hamster bile.
Digestive Diseases and Sciences, 1994
Taurohyodeoxycholic acid is a natural 6et-hydroxylated bile acid with an apparent hydrophilicity intermediate between those of tauroursodeoxycholic and taurocholic acids. We investigated in the rat the hepatobiliary metabolism, choleretic properties, and biliary maximum secretory rate (SRmax) of taurohyodeoxycholic in comparison with these two bile salts. Each compound was infused intravenously, at a rate increased in a stepwise manner from 100 to 300 nmol/min/100 g body wt, in bile salt-depleted bile fistula rats. The three bile salts appeared rapidly starting with the infusion and increased to represent more than 95% of the total bile salts. No apparent biliary metabolites were formed. All the bile salts caused a dose-dependent increase in bile flow and biliary lipid output. The absolute increase in bile flow was lower in rats infused with taurohyodeoxycholic acid, yet the volume of bile formed per nanomole of secreted bile salt was 13.8 nl for taurohyodeoxycholic, 6.4 nl for tauroursodeoxycholic acid, and 10.9 nl for taurocholic. The SRm~, , values were 1080, 3240, and 960 nmol/min/100 g, respectively. At all infusion rates, taurohyodeoxycholic acid caused a greater (P < 0.001) secretion of biliary lecithin compared to the other bile salts. There were no significant differences in the biliary secretion of cholesterol and proteins. Electron microscopy showed the recruitment of vesicles and lamellar bodies around and within bile canaliculi. In conclusion, taurohyodeoxycholic promotes a biliary lecithin secretion greater than expected from physicochemical predictions, representing a novel secretory property with potential pharmacological relevance.
Comparative Biochemistry and Physiology Part A: Physiology, 1996
Dose-response curves for taurocholate and tauroursodeoxycholate were performed in rat and rabbit livers to get more insight into species differences in the hepatic bile acid uptake. The bile acids showed saturation kinetics in both animals, the V,,, in rat being higher than in rabbit and the K, being lower in the rat than in the rabbit for both the bile acids, with no significant difference in the hepatic cells morphometric parameters. Therefore, it is possible that differences in the kinetic parameters are related to the number and, to a lesser extent, to the affinity of the transporters on the sinusoidal plasma membranes. COMP BIOCHEM PHYSIC),. 113A:2:157-164. 1996.
The effect of taurine depletion with guanidinoethanesulfonate on bile acid metabolism in the rat
Life Sciences, 1985
~dministration of guanidinoethanesulfonate (GES) to male rats for 5 weeks resulted in a 90% decrease in the hepatic taurine concentration. This depletion of hepatic taurine was associated with a 570% increase in the concentration of glycine-conjugated bile acids, a 30 % decrease in the concentration of taurine-conjugated bile acids, and an increase in the ratio of glycine-to taurine-conjugated bile acids from 0.046 to 0.45. The total concentration of bile salts in the bile and the turnover of cholic acid were not affected by administration of GE~ The data indicate that the taurine-depleted rat conserves taurine to some extent by using glycine instead of taurine for bile salt synthesis but not by decreasing the daily fractional turnover of bile acids.
Effect of sodium taurolithocholate on bile flow and bile acid excretion
Journal of Clinical Investigation, 1968
obstruction of segments of the biliary tree by precipitates of sodium taurolithocholate and possibly to a decrease in water entry into the biliary tree during infusion of this bile acid salt. lanoyl taurine; taurodeoxycholic acid, 3a, 12a,-dihydroxy-5p6-cholanoyl taurine; taurocholic acid, 3a, 7a, 12a-trihydroxy-5j3-cholanoyl taurine; taurocholenic acid, 3fthydroxy-5-cholenoyl taurine; muricholic acids, 3a, 6fl, 7atrihydroxy-5#-cholanoic acid, 3a, 6#3, 7fi-trihydroxy-5#cholanoic acid.
Biochimica et biophysica acta, 1986
Studies were carried out using an isolated rat liver system to define: the contribution of exogenous phosphatidylcholine (PC) to biliary phospholipid secretion; and its hepatic metabolism during perfusion of the livers with conjugated bile salts with different hydrophilic/hydrophobic properties. A tracer dose of sn-1-palmitoyl-sn-2-[14C]linoleoylPC was injected as a bolus into the recirculating liver perfusate, under constant infusion of 0.75 mumol/min of tauroursodeoxycholate or taurodeoxycholate. The effects on bile flow, biliary lipid secretion, 14C disappearance from the perfusate and its appearance in bile, as well as hepatic and biliary biotransformation were determined. With both the bile salts, about 40% of the [14C]PC was taken up by the liver from the perfusate over 100 min. During the same period less than 2% of the given radioactivity was secreted into bile. More than 95% of the 14C recovered in bile was located within the identical injected PC molecular species. The bil...
Gastroenterology, 1995
To explain the greater hepatoprotective effect of tauroursodeoxycholic acid vs. ursodeoxycholic acid, the absorption, hepatic enrichment, and biotransformation of these bile acids (250 mg/ day) were compared in rats. Methods: Bile acids were determined in intestinal contents, feces, urine, plasma, and liver by gas chromatography-mass spectrometry. Results: The concentration of ursodeoxycholate in the liver of animals administered tauroursodeoxycholic acid (175 _+ 29 nmol/g) was greater (P < 0.05) than in animals administered ursodeoxycholic acid (79 + 19 nmol/g). Hepatic lithocholate was substantially higher after ursodeoxycholic acid administration (21 _+ 10 nmol/g) than after tauroursodeoxycholic acid administration (12 _+ 1 nmol/g). A concomitant reduction in the proportion of hydrophobic bile acids occurred that was greatest during tauroursodeoxycholic acid administration. In the intestinal tract, the mass of ursodeoxycholate and its specific metabolites was greater in rats administered tauroursodeoxycholic acid (27.2 mg) than those administered ursodeoxycholic acid (13.2 mg). In feces, the proportion of lithocholate was 21.9% _+ 4.9% and 5.4% _+ 4.0% after ursodeoxycholic acid and tauroursodeoxycholic acid administration, respectively. Conclusions: Compared with ursodeoxycholic acid, tauroursodeoxycholic acid induces a greater decrease in the percent composition of more hydrophobic bile acids within the pool, limits lithocholate formation, and increases hepatic ursodeoxycholate concentration. These differences are explained by increased hepatic extraction and reduced intestinal biotransformation and not by enhanced absorption of the amidated species.