Biliary excretion of biotin and biotin metabolites is quantitatively minor in rats and pigs

Janos Zempleni, Gary M. Green, Alan W. Spannagel, Donald M. Mock

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

We sought to determine whether the biliary excretion of biotin contributes substantially to the overall excretion of the vitamin in mammals, and hence, whether metabolism by gut microorganisms could account for some metabolism of biotin administered parenterally, [carbonyl-14C]Biotin was injected intravenously into six rats; bile and urine were collected for 24 h after injection. In a study of five pigs, serum and bile were analyzed for endogenous biotin and metabolites. In rat bile and urine, biotin, bisnorbiotin, biotin-d,l-sulfoxide, bisnorbiotin methyl ketone and two unidentified compounds were quantitated. In bile, these six compounds accounted for only 1.9 ± 0.2% of the administered 14C, but in urine they accounted for 60.6 ± 4.1%. The metabolite and time profiles in bile were also strikingly different from those in urine. Only biotin, bisnorbiotin and biotin-d,l-sulfoxide were quantitated in pig bile and serum. The concentrations of biotin, bisnorbiotin and biotin-d,l-sulfoxide in bile were 6.9-14.7 times the concentrations in serum. However, the bile to serum ratios of biotin and metabolites were >99% less than those of bilirubin, which is actively excreted. These data provide evidence that the biliary excretion of biotin and metabolites is quantitatively negligible.

Original languageEnglish (US)
Pages (from-to)1496-1500
Number of pages5
JournalJournal of Nutrition
Volume127
Issue number8
DOIs
StatePublished - 1997

Keywords

  • Bile
  • Biotin
  • Pigs
  • Rats

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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