The role of conjugation reactions in enhancing biliary secretion of bile acids.

  title={The role of conjugation reactions in enhancing biliary secretion of bile acids.},
  author={Donald A. Vessey and Joanne O. Whitney and John L. Gollan},
  journal={The Biochemical journal},
  volume={214 3},
Shortening the five-carbon carboxylic acid side chain of cholic acid by one methylene group gave rise to a bile acid (norcholate) that was not a substrate for the bile acid-conjugating enzymes. The metabolism and biliary secretion of norcholate in intact liver was examined in the isolated perfused rat liver system. When rat livers were perfused with 14-20 microM solutions of norcholate for 10 min, norcholate was found in the unconjugated form in liver, venous effluent and bile. Neither… 
Effect of side-chain shortening on the physiologic properties of bile acids: hepatic transport and effect on biliary secretion of 23-nor-ursodeoxycholate in rodents.
It is proposed that a fraction of nor-UDC is secreted into canalicular bile in the unconjugated form and is protonated by a hydrogen ion derived from carbonic acid that was generated by the hydration of luminal CO2 by carbonic anhydrase present in biliary ductular cells.
Bile acid conjugation pattern in the isolated perfused rat liver during infusion of an amino acid formulation.
Data indicate that taurine availability, even in the presence of high concentrations of glycine and other amino acids in Trophamine, appears to be the most important factor in determining the pattern of bile acid conjugation in the isolated perfused rat liver.
Biological properties of the 2-fluoro-beta-alanine conjugates of cholic acid and chenodeoxycholic acid in the isolated perfused rat liver.
The data demonstrate that the biological properties of the 2-fluoro-beta-alanine conjugates of cholic acid and chenodeoxycholic acid are not markedly different from those of the naturally occurring taurine and glycine conjugs, and suggest that the amino acid moiety can influence the biliary secretion and cholestatic properties of chenodesoxycholics acid conjugate.
Purification and characterization of the enzymes of bile acid conjugation from fish liver.
Since it appears to be the rate controlling enzyme in all species, it is expected that the rate of bile acid conjugation is much slower in non-mammalian liver as compared to mammalian liver.
Differential regulation of cytosolic and peroxisomal bile acid amidation by PPAR alpha activation favors the formation of unconjugated bile acids.
The results from this study suggest that an increased formation of unconjugated bile acids occurs during PPARalpha activation.
Mechanisms of Bile Secretion and Hepatic Transport
Bile is a complex aqueous secretion that is elaborated by the liver of all vertebrate species, stored in the gallbladder, and discharged into the common hepatic duct and intestine. Its primary source
Effects of uridine diphosphate glucuronosyltransferase activity on the maximal secretion rate of bilirubin conjugates in the rat.
The studies suggest that the conjugation rate in vivo rather than the biliary secretion step is the major determinant of the maximal bilirubin secretion rate, and an equilibration of bilirUBin pigments between plasma, liver, and bile.
Effect of side chain length on biotransformation, hepatic transport, and choleretic properties of chenodeoxycholyl homologues in the rodent: Studies with dinorchenodeoxycholic acid, norchenodeoxycholic acid, and chenodeoxycholic acid
DinorCDCA is the first dihydroxy bile acid to be identified that is secreted largely in unconjugated form in bile, and induces hypercholeresis.
Enzymology of Amino Acid Conjugation Reactions
Amino acid conjugation is a route of metabolism for various xenobiotic carboxylic acids and bile acids; however, knowledge of the enzymology (e.g., multiplicity of enzymes, substrate selectivity,
Hepatic Bile Acid Transport and Secretion
Bile acid transport and secretion by the liver is one of the important steps in the recirculation of bile acid within the body. After bile acids return from the intestine, they have first to be taken