Glucoside formation as a novel metabolic pathway of pantothenic acid in the dog.
Metabolism of pantothenic acid (PaA) in beagle dogs was investigated. The dogs excreted 12.3% of the dose in the urine within 24 hr after a single oral administration of [3H]PaA (3 mg/kg). High performance liquid chromatographic analysis of the urine showed the presence of unchanged vitamin and a major metabolite, which accounted for 60.2 and 39.8% of the urinary radioactivity respectively. Although the metabolite was hydrolyzed by treatment with beta-glucuronidase or acid phosphatase, it was found that this hydrolysis resulted from the actions of beta-glucosidase contained as a contaminant in these enzyme preparations. beta-Glucosidase completely hydrolyzed the metabolite to generate PaA and glucose. The metabolite was isolated and subjected to GC/MS and NMR analyses. It was identical to synthetic PaA beta-glucoside, 4'-O-(beta-D-glucopyranosyl)-D-pantothenic acid. It was shown by the use of dog liver microsomes that PaA underwent beta-glucosidation in the presence of uridine diphosphate glucose (UDPG). It is proposed that beta-glucosidation by UDP-glucosyltransferase is a novel metabolic pathway of PaA in the dog.
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004285:Dogs; D014453:Glucuronosyltransferase / Q000494:pharmacology; D006868:Hydrolysis; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010205:Pantothenic Acid / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism* / Q000652:urine; D001617:beta-Glucosidase / Q000494:pharmacology
D010205:Pantothenic Acid; C019513:D-pantothenic acid 4'-O-beta-glucoside; D014453:Glucuronosyltransferase; D001617:beta-Glucosidase