Long-term kinetic study of β-carotene, using accelerator mass spectrometry in an adult volunteer

S. R. Dueker, Y. Lin, B. A. Buchholz, Philip D Schneider, M. W. Lame, H. J. Segall, J. S. Vogel, A. J. Clifford

Research output: Contribution to journalArticle

73 Scopus citations

Abstract

We present a sensitive tracer method, suitable for in vivo human research, that uses β-[14C]carotene coupled with accelerator mass spectrometry (AMS) detection. Using this approach, the concentration-time course of a physiological (306 μg; 200 nCi) oral dose of β-[14C]carotene was determined for 209 days in plasma. Analytes included β-[14C]carotene, [14C]retinyl esters, [14C]retinol, and several [14C]retinoic acids. There was a 5.5-h lag between dosing and the appearance of 14C in plasma. Labeled β-carotene and [14C]retinyl esters rose and displayed several maxima with virtually identical kinetic profiles over the first 24-h period; elevated [14C]retinyl ester concentrations were sustained in the plasma compartment for >21 h postdosing. The appearance of [14C]retinol in plasma was also delayed 5.5 h postdosing and its concentration rose linearly for 28 h before declining. Cumulative urine and stool were collected for 17 and 10 days, respectively, and 57.4% of the dose was recovered in the stool within 48 h postdosing. The stool was the major excretion route for the absorbed dose. The turnover times (1/k(el)) for β-carotene and retinol were 58 and 302 days, respectively. Area under the curve analysis of the plasma response curves suggested a molar vitamin A value of 0.53 for β-carotene, with a minimum of 62% of the absorbed β-carotene being cleaved to vitamin A. In summary, AMS is an excellent tool for defining the in vivo metabolic behavior of β-carotene and related compounds at physiological concentrations. Further, our data suggest that retinyl esters derived from β-carotene may undergo hepatic resecretion with VLDL in a process similar to that observed for β-carotene.

Original languageEnglish (US)
Pages (from-to)1790-1800
Number of pages11
JournalJournal of Lipid Research
Volume41
Issue number11
StatePublished - 2000

Keywords

  • Human
  • Isotope
  • Vitamin A

ASJC Scopus subject areas

  • Endocrinology

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    Dueker, S. R., Lin, Y., Buchholz, B. A., Schneider, P. D., Lame, M. W., Segall, H. J., Vogel, J. S., & Clifford, A. J. (2000). Long-term kinetic study of β-carotene, using accelerator mass spectrometry in an adult volunteer. Journal of Lipid Research, 41(11), 1790-1800.