title: Hydrolysis and absorption of a conjugate of ursodeoxycholic acid with para-aminobenzoic acid.
abstract: Hydrolysis of ursodeoxycholyl-p-aminobenzoic acid (PABA-UDCA), a synthetic bile acid conjugate used for the evaluation of the activity of intestinal bacterial growth, was studied with pancreatic enzymes, carboxypeptidase A, carboxypeptidase B, trypsin alpha-chymotrypsin, cholylglycine hydrolase, liver homogenate, small intestinal homogenates, and plasma, in comparison with the hydrolysis of glycocholic acid, ursodeoxycholyl-L-leucine (L-Leu-UDCA), and ursodeoxycholyl-L-lysine (L-Lys-UDCA). PABA-UDCA was specifically cleaved by bacterial cholylglycine hydrolase to ursodeoxycholic acid and para-aminobenzoic acid (PABA), but not by pancreatic enzymes. L-Leu-UDCA was cleaved by pancreatic enzymes, carboxypeptidase A, and cholylglycine hydrolase. L-Lys-UDCA was cleaved by pancreatic enzymes, carboxypeptidase B, and cholylglycine hydrolase. The small amount of glycocholic acid was cleaved by pancreatic enzymes and carboxypeptidase A and B, and cholylglycine hydrolase hydrolyzed glycocholic acid completely. In everted gut sac experiments, PABA-UDCA was absorbed by active transport in the rat terminal ileum, and the same rate of PABA was absorbed by passive diffusion in the four segments of the rat small intestine. These observations indicate that PABA-UDCA test can evaluate the activity of small intestinal bacterial growth.
authors.affiliation: Department of Pharmacy, Chugoku Rosai Hospital, Hiroshima, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Maeda
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
mesh_terms: D010129:4-Aminobenzoic Acid / Q000378:metabolism / Q000493:pharmacokinetics; D000581:Amidohydrolases / Q000378:metabolism; D000818:Animals; D001419:Bacteria / Q000254:growth & development; D001426:Bacterial Proteins / Q000378:metabolism; D043424:Carboxypeptidase B; D002268:Carboxypeptidases / Q000378:metabolism; D043422:Carboxypeptidases A; D002918:Chymotrypsin / Q000378:metabolism; D003840:Deoxycholic Acid / Q000031:analogs & derivatives*; D005069:Evaluation Studies as Topic; D006868:Hydrolysis; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism; D007421:Intestine, Small / Q000378:metabolism; D007422:Intestines / Q000382:microbiology; D008099:Liver / Q000378:metabolism; D008297:Male; D010179:Pancreas / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D013379:Substrate Specificity; D014357:Trypsin / Q000378:metabolism; D014580:Ursodeoxycholic Acid / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics; D062366:para-Aminobenzoates
chemical_list: D001426:Bacterial Proteins; D062366:para-Aminobenzoates; D003840:Deoxycholic Acid; C055705:PABA-ursodeoxycholic acid; D014580:Ursodeoxycholic Acid; D002268:Carboxypeptidases; D043422:Carboxypeptidases A; D043424:Carboxypeptidase B; D002918:Chymotrypsin; D014357:Trypsin; D000581:Amidohydrolases; C023154:choloylglycine hydrolase; D010129:4-Aminobenzoic Acid