Intestinal absorption and metabolism of 9-cis-beta-carotene in vivo: biosynthesis of 9-cis-retinoic acid.
This study was done to examine the intestinal absorption and cleavage of 9-cis-beta-carotene in vivo. A micellar solution, containing either no addition or 10 mumol of 9-cis- or all-trans-beta-carotene, was perfused for 2 h through the upper portion of the small intestine of ferrets. The effluent of a mesenteric lymph duct cannulation was collected, as well as intestinal mucosa scrapings, a portal blood sample, and a liver biopsy, both before and after perfusion. Carotenoids and retinoids were measured by reverse-phase, high performance liquid chromatography. 9-Cis- and all-trans-beta-carotene were transported equally well into mesenteric lymph, although the intestinal concentration of the corresponding isomer was tenfold higher after perfusion of the 9-cis- isomer than after perfusion of all-trans-beta-carotene. Regardless of which isomer was used, perfusion of beta-carotene resulted in the biosynthesis of similar amounts of retinoic acid in portal blood, liver, and intestine. However, after the perfusion of all-trans-beta-carotene, all the retinoic acid formed was in the all-trans- form, whereas the perfusion of 9-cis-beta-carotene resulted in the biosynthesis of about 50% of the total retinoic acid as the 9-cis-isomer. We conclude that in the in vivo ferret model, 9-cis-beta-carotene has a good bioavailability and is a precursor of 9-cis-retinoic acid.
Hébuterne
X
X
United States Department of Agriculture, Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA.
Wang
X D
XD
Johnson
E J
EJ
Krinsky
N I
NI
Russell
R M
RM
D000818:Animals; D002338:Carotenoids / Q000378:metabolism* / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid; D005289:Ferrets; D007408:Intestinal Absorption; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008196:Lymph / Q000378:metabolism; D008297:Male; D008823:Micelles; D010477:Perfusion; D011168:Portal System / Q000378:metabolism; D014212:Tretinoin / Q000378:metabolism*; D019207:beta Carotene
D008823:Micelles; D019207:beta Carotene; D002338:Carotenoids; D014212:Tretinoin