Dietary β-Carotene Is Taken up by Blood Plasma and Leukocytes in Dogs

• Published in: The Journal of nutrition Vol. 130; no. 7; pp. 1788 - 1791
• Main Authors: Chew, Boon P., Park, Jean Soon, Weng, Brian C., Wong, Teri S., Hayek, Michael G., Reinhart, Gregory A.
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01.07.2000; American Society for Nutritional Sciences
• Subjects: Animals; beta Carotene - blood; beta Carotene - pharmacokinetics; Biological and medical sciences; canine; Dogs - metabolism; Enzymes. Coenzymes. Vitamins. Pigments; Female; Fundamental and applied biological sciences. Psychology; leukocytes; Leukocytes - metabolism; Metabolisms and neurohumoral controls; Models, Biological; Neutrophils - metabolism; plasma; uptake; Vertebrates: anatomy and physiology, studies on body, several organs or systems; β-carotene; β-carotene; leukocytes; canine; plasma; uptake; Fissipedia; Carnivora; Leukocyte; Metabolism; Uptake; Blood plasma; Micronutrient; Vertebrata; Mammalia; Absorption; Betacarotene; Carotenoid; Dog
• ISSN: 0022-3166; 1541-6100
• DOI: 10.1093/jn/130.7.1788

β-Carotene uptake by blood plasma and leukocytes was studied in mature beagle dogs. In expt. 1, dogs were fed once orally with 0, 50, 100 or 200 mg of β-carotene and their blood was sampled at 0, 1.5, 3, 6, 10, 18 and 24 h. Plasma β-carotene concentrations increased dose-dependently to peak at 6 h postfeeding. Concentrations decreased rapidly thereafter, showing a half-life of 3 to 4 h. In expt. 2, dogs were given daily doses for seven consecutive days with 0, 12.5, 25, 50 or 100 mg β-carotene. Plasma β-carotene concentrations increased dose-dependently; concentrations after the last dose were two- to fourfold higher than after the first dose. In expt. 3, dogs were fed 0, 50 or 100 mg β-carotene daily for 30 d. β-Carotene was elevated in lymphocytes and neutrophils in supplemented dogs. Furthermore, β-carotene was taken up by the cytosol, mitochondria, microsomes (lymphocytes and neutrophils) and nuclei (lymphocytes only), proving that dogs can absorb β-carotene. β-Carotene is taken up by subcellular organelles of blood lymphocytes and neutrophils and in the plasma and leukocytes β-carotene may have physiological importance as it relates to immunity in dogs. Uptake kinetics indicated that dogs are not an appropriate animal model for studying β-carotene absorption and metabolism in humans.