title: Absorption and conversion of 11,12-(3)H-beta-carotene to vitamin A in Sprague-Dawley rats of different vitamin A status.
abstract: The aim of this study was to determine the bioavailability and bioconversion to vitamin A of a single oral dose in oil or an aqueous dispersion of labeled beta-carotene in rats of different vitamin A status. Weanling Sprague-Dawley rats were fed a vitamin A-deficient diet and supplemented for 4 wk with 0, 7, 21 and 63 micro g/(rat. d) of retinyl acetate. The rats, of different vitamin A status, were then given a single oral dose of 11,12-(3)H-beta-carotene (0.15 micro mol) dissolved in corn oil or dispersed in aqueous Tween 80. The rats were killed 4 or 24 h after the dose, and serum, liver, the entire digestive tract, other tissues, urine and feces were analyzed for carotenoids, retinoids and associated radioactivity. At 4 h after the dose, 85 +/- 9% of the administered radioactivity was recovered. Almost 50% of the dose was present as intact beta-carotene in the large intestine where further absorption and conversion was ruled out. The absorption of beta-carotene was very low, and < 5% of the radioactive dose was converted to retinoids. The absorption and conversion to vitamin A did not differ among rats of different vitamin A status. The results suggest that a single oral dose of beta-carotene might not be an effective way of raising vitamin A stores in the body.
authors.affiliation: Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, Ames 50011, USA.
authors.forename: Bhabesh C
authors.initials: BC
authors.lastname: Goswami
authors.forename: Kristi D
authors.initials: KD
authors.lastname: Ivanoff
authors.forename: Arun B
authors.initials: AB
authors.lastname: Barua
mesh_terms: D000284:Administration, Oral; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001682:Biological Availability; D007408:Intestinal Absorption; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution; D014801:Vitamin A / Q000096:biosynthesis*; D014802:Vitamin A Deficiency / Q000378:metabolism*; D019207:beta Carotene / Q000378:metabolism / Q000493:pharmacokinetics*
chemical_list: D019207:beta Carotene; D014801:Vitamin A