Vitamin E enhances the lymphatic transport of beta-carotene and its conversion to vitamin A in the ferret.
OBJECTIVE
beta-Carotene and alpha-tocopherol may have either antagonistic or synergistic effects on each other's absorption and metabolism. The effects of both physiological and pharmacological concentrations of alpha-tocopherol on the absorption and metabolism of beta-carotene in ferret intestine were determined.


METHODS
A high concentration of beta-carotene was perfused through the upper portion of the small intestine of ferrets in vivo with varying levels of alpha-tocopherol. The effluent of a mesenteric lymph duct cannulation, the intestinal mucosal scraping, and portal vein blood were sampled and analyzed by high-performance liquid chromatography.


RESULTS
The lymphatic transport of beta-carotene was enhanced 4-fold by alpha-tocopherol at a physiological dose and 12-21-fold at a pharmacological dose. The lymphatic transport of alpha-tocopherol was linearly (r = 0.8; P < 0.05) related to the luminal alpha-tocopherol concentration even in the presence of a high concentration of beta-carotene. Furthermore, alpha-tocopherol increased the conversion of beta-carotene into retinol in the intestine in a dose-dependent manner.


CONCLUSIONS
alpha-Tocopherol has a positive effect on the intestinal absorption of intact beta-carotene and may modulate the metabolic conversion of beta-carotene into retinoids.
Wang
X D
XD
Gastrointestinal Nutrition Laboratory, U.S. Department of Agriculture Human Nutrition Research Center, Boston, Massachusetts.
Marini
R P
RP
Hebuterne
X
X
Fox
J G
JG
Krinsky
N I
NI
Russell
R M
RM
D000042:Absorption; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002338:Carotenoids / Q000378:metabolism*; D005289:Ferrets; D007413:Intestinal Mucosa / Q000378:metabolism; D008208:Lymphatic System / Q000378:metabolism*; D008297:Male; D011169:Portal Vein; D014801:Vitamin A / Q000097:blood / Q000378:metabolism*; D014810:Vitamin E / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D019207:beta Carotene
D019207:beta Carotene; D014801:Vitamin A; D014810:Vitamin E; D002338:Carotenoids