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 language | English (US) |
|---|---|
| Pages (from-to) | 1790-1800 |
| Number of pages | 11 |
| Journal | Journal of Lipid Research |
| Volume | 41 |
| Issue number | 11 |
| State | Published - 2000 |
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Keywords
- Human
- Isotope
- Vitamin A
ASJC Scopus subject areas
- Endocrinology
Cite this
Long-term kinetic study of β-carotene, using accelerator mass spectrometry in an adult volunteer. / Dueker, S. R.; Lin, Y.; Buchholz, B. A.; Schneider, Philip D; Lame, M. W.; Segall, H. J.; Vogel, J. S.; Clifford, A. J.
In: Journal of Lipid Research, Vol. 41, No. 11, 2000, p. 1790-1800.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Long-term kinetic study of β-carotene, using accelerator mass spectrometry in an adult volunteer
AU - Dueker, S. R.
AU - Lin, Y.
AU - Buchholz, B. A.
AU - Schneider, Philip D
AU - Lame, M. W.
AU - Segall, H. J.
AU - Vogel, J. S.
AU - Clifford, A. J.
PY - 2000
Y1 - 2000
N2 - 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.
AB - 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.
KW - Human
KW - Isotope
KW - Vitamin A
UR - http://www.scopus.com/inward/record.url?scp=0033730058&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033730058&partnerID=8YFLogxK
M3 - Article
C2 - 11060348
AN - SCOPUS:0033730058
VL - 41
SP - 1790
EP - 1800
JO - Journal of Lipid Research
JF - Journal of Lipid Research
SN - 0022-2275
IS - 11
ER -