![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
Manuscript received 25 February 1997. Initial reviews completed 19 March 1997. Revision accepted 23 April 1997.
Department of Pediatrics, University of Arkansas for Medical Science/Arkansas Children's Hospital Research Institute, Little Rock, AR 72202 and * Department of Physiology, University of Texas Health Science Center, San Antonio, TX 78284
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.
Key words: biotin, bile, rats, pigs.
This article has been cited by other articles:
|
|
 |
|
  B. Lewis, S. Rathman, and R. McMahon Dietary Biotin Intake Modulates the Pool of Free and Protein-Bound Biotin in Rat Liver J. Nutr., September 1, 2001; 131(9): 2310 - 2315. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Zempleni and D. M Mock Bioavailability of biotin given orally to humans in pharmacologic doses Am. J. Clinical Nutrition, March 1, 1999; 69(3): 504 - 508. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Zempleni and D. M. Mock Advanced Analysis of Biotin Metabolites in Body Fluids Allows a More Accurate Measurement of Biotin Bioavailability and Metabolism in Humans J. Nutr., February 1, 1999; 129(2): 494 - 494. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K.-S. Wang, N. I. Mock, and D. M. Mock Biotin Biotransformation to Bisnorbiotin Is Accelerated by Several Peroxisome Proliferators and Steroid Hormones in Rats J. Nutr., November 1, 1997; 127(11): 2212 - 2216. [Abstract] [Full Text]
|
|
