The transport of α-tocopherol and β-carotene in human blood

• Published in: Journal of lipid research 1976-07, Vol.17 (4), p.343-352
• Main Authors: Bjornson, L K, Kayden, H J, Miller, E, Moshell, A N
• Format: Article
• Language: English
• Subjects: Adult; antioxidant hyperlipoproteinemia; Biological Transport; Carotenoids - blood; Carotenoids - therapeutic use; Cholesterol - blood; erythropoietic protoporphyria; Female; Humans; Hyperlipidemias - blood; Lipoproteins, HDL - blood; Lipoproteins, LDL - blood; Lipoproteins, VLDL - blood; Male; Middle Aged; Phospholipids - blood; Porphyrias - blood; Porphyrias - drug therapy; singlet oxygen quenching; Triglycerides - blood; Vitamin E - blood; Vitamin E - therapeutic use
• ISSN: 0022-2275; 1539-7262
• DOI: 10.1016/S0022-2275(20)34917-8

The concentrations and distributions of major lipids (cholesterol, phospholipid, and triglyceride), tocopherol and carotenoids were determined in the plasma lipoprotein fractions (VLDL, LDL, and HDL) of (1) normal human subjects, (2) patients with hyperlipoproteinemia, and (3) patients with erythropoietic protoporphyria treated with oral β-carotene and/or α-tocopherol. The distribution of tocopherol (in percent) was most closely correlated with the distribution of total lipids in the individual lipoproteins, while the major portion of β-carotene was present in the low density lipoproteins, irrespective of the lipid distribution in the lipoproteins (except for one subject with hyperchylomicronemia). The α-tocopherol and β-carotene concentrations of plasma and RBC in patients treated with tocopherol and carotene were determined periodically for a one-year period. Plasma and RBC tocopherol concentrations showed a rapid, parallel increase in response to tocopherol supplementation. In contrast, the plasma and RBC carotene concentrations showed a much slower and nonparallel increase in response to carotene administration. When carotene supplementation was stopped, the elevated carotene levels in both plasma and RBC persisted for several months; the elevated plasma carotene level persisted longer than the raised RBC carotene levels. These results suggest that α-tocopherol and β-carotene are transported differently in the circulation and that the tissue storage and mobilization of these compounds are different.